Potential fix for code scanning alert no. 1: 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: Kurt Garloff <[email protected]>

Author: garloff

.github/workflows/yaml2ics.yml

@@ -7,6 +7,8 @@ on:
   workflow_dispatch:
 jobs:
   default:
+    permissions:
+      contents: write
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v3