github: Add contents: read to job permissions (#785)

Author: bkeryan

.github/workflows/CI.yml

@@ -29,5 +29,6 @@ jobs:
     needs: [run_unit_tests, run_system_tests]
     if: always()
     permissions:
+      contents: read
       checks: write
       pull-requests: write

.github/workflows/PR.yml

@@ -17,5 +17,6 @@ jobs:
     name: Run CI
     uses: ./.github/workflows/CI.yml
     permissions:
+      contents: read
       checks: write
       pull-requests: write

.github/workflows/report_test_results.yml

@@ -9,6 +9,7 @@ jobs:
     name: Report test results
     runs-on: ubuntu-latest
     permissions:
+      contents: read
       checks: write
       pull-requests: write
     steps: