ci: fix Docker image publishing

Author: yann-soubeyrand

.github/workflows/ghcr.yaml

@@ -9,6 +9,10 @@ jobs:
   build-and-push:
     runs-on: ubuntu-latest
 
+    permissions:
+      contents: read
+      packages: write
+
     steps:
       - name: Checkout repository
         uses: actions/checkout@v3