docker: update README to add ghcr.io (#6677)

.github/workflows/docker.yml

@@ -12,6 +12,9 @@ on:
 jobs:
   buildx:
     runs-on: ubuntu-latest
+    permissions:
+      actions: write
+      contents: read
     steps:
       - name: Canel previous runs on main
         if: ${{ github.event_name == 'push' && github.ref == 'refs/heads/main' }}