Migrate Renovate config (#169462)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

.github/renovate.json

@@ -6,7 +6,7 @@
     "pep621",
     "pip_requirements",
     "pre-commit",
-    "regex",
+    "custom.regex",
     "homeassistant-manifest"
   ],
 
@@ -27,8 +27,9 @@
     ]
   },
 
-  "regexManagers": [
+  "customManagers": [
     {
+      "customType": "regex",
       "description": "Update ruff required-version in pyproject.toml",
       "managerFilePatterns": ["/^pyproject\\.toml$/"],
       "matchStrings": ["required-version = \">=(?<currentValue>[\\d.]+)\""],