test: set permissions: content: read

Suggested by @naveensrinivasan

.github/workflows/automated-tests.yml

@@ -7,6 +7,8 @@ on:
       - 'v[3-9].*.x-release'
   pull_request:
     types: [opened, synchronize, reopened]
+permissions:
+  contents: read
 jobs:
   build-install-and-test:
     runs-on: ubuntu-20.04
@@ -137,4 +139,4 @@ jobs:
           name: tests-report
           path: |
             bigbluebutton-tests/playwright/playwright-report
-            bigbluebutton-tests/playwright/test-results
+            bigbluebutton-tests/playwright/test-results