Potential fix for code scanning alert no. 7: Workflow does not contain permissions (#581)

Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

.github/workflows/testing.yml

@@ -1,5 +1,8 @@
 name: Testing
 
+permissions:
+  contents: read
+
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
   cancel-in-progress: true