Potential fix for code scanning alert no. 4: Workflow does not contain permissions

Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>
Signed-off-by: John Lago <750845+Lagoja@users.noreply.github.com>

Author: Lagoja

.github/workflows/random-reviewer-assignment.yml

@@ -3,6 +3,10 @@ on:
   pull_request:
     types: [opened]
 
+permissions:
+  contents: read
+  pull-requests: write
+
 env:
   GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}