Add explicit permissions to CI workflow jobs for security

Co-authored-by: jbltx <1284323+jbltx@users.noreply.github.com>

.github/workflows/ci.yml

@@ -10,6 +10,8 @@ jobs:
   build-and-test:
     name: Build and Test - BCM${{ matrix.bcm }}
     runs-on: ubuntu-latest
+    permissions:
+      contents: read
     strategy:
       matrix:
         bcm: [2835, 2836, 2837]
@@ -87,6 +89,8 @@ jobs:
   run-integration-tests:
     name: Run Integration Tests
     runs-on: ubuntu-latest
+    permissions:
+      contents: read
     needs: build-and-test
     
     steps: