patch 9.0.0593: CI actions have too many permissions

Problem:    CI actions have too many permissions.
Solution:   Restrict permissions to what is required. (closes #11223)

.github/workflows/coverity.yml

@@ -4,6 +4,9 @@ on:
     - cron: '42 0 * * *'  # Run once per day, to avoid Coverity's submission limits
   workflow_dispatch:
 
+permissions:
+  contents: read # to fetch code (actions/checkout)
+
 jobs:
   scan:
     runs-on: ubuntu-20.04