Bump symfony/http-foundation from 3.3.6 to 3.4.39

Bumps [symfony/http-foundation](https://github.com/symfony/http-foundation) from 3.3.6 to 3.4.39.
- [Release notes](https://github.com/symfony/http-foundation/releases)
- [Changelog](https://github.com/symfony/http-foundation/blob/master/CHANGELOG.md)
- [Commits](https://github.com/symfony/http-foundation/compare/v3.3.6...v3.4.39)

Signed-off-by: dependabot[bot] <support@github.com>

composer.lock

@@ -1,7 +1,7 @@
 {
     "_readme": [
         "This file locks the dependencies of your project to a known state",
-        "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#composer-lock-the-lock-file",
+        "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
     "content-hash": "82f30d1a5607b0db9092eb88a3f265ea",
@@ -734,6 +734,7 @@
             "keywords": [
                 "microframework"
             ],
+            "abandoned": "symfony/flex",
             "time": "2017-07-23T07:40:14+00:00"
         },
         {
@@ -857,29 +858,30 @@
         },
         {
             "name": "symfony/http-foundation",
-            "version": "v3.3.6",
+            "version": "v3.4.39",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/http-foundation.git",
-                "reference": "49e8cd2d59a7aa9bfab19e46de680c76e500a031"
+                "reference": "a8833c56f6a4abcf17a319d830d71fdb0ba93675"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/symfony/http-foundation/zipball/49e8cd2d59a7aa9bfab19e46de680c76e500a031",
+                "url": "https://api.github.com/repos/symfony/http-foundation/zipball/a8833c56f6a4abcf17a319d830d71fdb0ba93675",
-                "reference": "49e8cd2d59a7aa9bfab19e46de680c76e500a031",
+                "reference": "a8833c56f6a4abcf17a319d830d71fdb0ba93675",
                 "shasum": ""
             },
             "require": {
-                "php": ">=5.5.9",
+                "php": "^5.5.9|>=7.0.8",
-                "symfony/polyfill-mbstring": "~1.1"
+                "symfony/polyfill-mbstring": "~1.1",
+                "symfony/polyfill-php70": "~1.6"
             },
             "require-dev": {
-                "symfony/expression-language": "~2.8|~3.0"
+                "symfony/expression-language": "~2.8|~3.0|~4.0"
             },
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "3.3-dev"
+                    "dev-master": "3.4-dev"
                 }
             },
             "autoload": {
@@ -906,7 +908,7 @@
             ],
             "description": "Symfony HttpFoundation Component",
             "homepage": "https://symfony.com",
-            "time": "2017-07-21T11:04:46+00:00"
+            "time": "2020-03-23T12:14:52+00:00"
         },
         {
             "name": "symfony/http-kernel",
@@ -996,16 +998,16 @@
         },
         {
             "name": "symfony/polyfill-mbstring",
-            "version": "v1.5.0",
+            "version": "v1.15.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/polyfill-mbstring.git",
-                "reference": "7c8fae0ac1d216eb54349e6a8baa57d515fe8803"
+                "reference": "81ffd3a9c6d707be22e3012b827de1c9775fc5ac"
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             "dist": {
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-                "url": "https://api.github.com/repos/symfony/polyfill-mbstring/zipball/7c8fae0ac1d216eb54349e6a8baa57d515fe8803",
+                "url": "https://api.github.com/repos/symfony/polyfill-mbstring/zipball/81ffd3a9c6d707be22e3012b827de1c9775fc5ac",
-                "reference": "7c8fae0ac1d216eb54349e6a8baa57d515fe8803",
+                "reference": "81ffd3a9c6d707be22e3012b827de1c9775fc5ac",
                 "shasum": ""
             },
             "require": {
@@ -1017,7 +1019,7 @@
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "1.5-dev"
+                    "dev-master": "1.15-dev"
                 }
             },
             "autoload": {
@@ -1051,7 +1053,66 @@
                 "portable",
                 "shim"
             ],
-            "time": "2017-06-14T15:44:48+00:00"
+            "time": "2020-03-09T19:04:49+00:00"
+        },
+        {
+            "name": "symfony/polyfill-php70",
+            "version": "v1.15.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/symfony/polyfill-php70.git",
+                "reference": "2a18e37a489803559284416df58c71ccebe50bf0"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/symfony/polyfill-php70/zipball/2a18e37a489803559284416df58c71ccebe50bf0",
+                "reference": "2a18e37a489803559284416df58c71ccebe50bf0",
+                "shasum": ""
+            },
+            "require": {
+                "paragonie/random_compat": "~1.0|~2.0|~9.99",
+                "php": ">=5.3.3"
+            },
+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.15-dev"
+                }
+            },
+            "autoload": {
+                "psr-4": {
+                    "Symfony\\Polyfill\\Php70\\": ""
+                },
+                "files": [
+                    "bootstrap.php"
+                ],
+                "classmap": [
+                    "Resources/stubs"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "authors": [
+                {
+                    "name": "Nicolas Grekas",
+                    "email": "p@tchwork.com"
+                },
+                {
+                    "name": "Symfony Community",
+                    "homepage": "https://symfony.com/contributors"
+                }
+            ],
+            "description": "Symfony polyfill backporting some PHP 7.0+ features to lower PHP versions",
+            "homepage": "https://symfony.com",
+            "keywords": [
+                "compatibility",
+                "polyfill",
+                "portable",
+                "shim"
+            ],
+            "time": "2020-02-27T09:26:54+00:00"
         },
         {
             "name": "symfony/routing",