fix(ci): add contents: read permission to mcp-mysql manifest job

Author: kpiwko

.github/workflows/mcp-mysql.yaml

@@ -59,6 +59,7 @@ jobs:
     if: github.event_name != 'pull_request'
     runs-on: ubuntu-24.04
     permissions:
+      contents: read
       packages: write
 
     steps: