chore: Use PAT for registry push.

See:
- https://github.com/go-gitea/gitea/issues/23642
- https://github.com/go-gitea/gitea/issues/29398

.github/workflows/docker.yml

@@ -16,7 +16,6 @@ jobs:
         runs-on: ubuntu-latest
         permissions:
             contents: read
-            packages: write
         steps:
             - name: Checkout
               uses: actions/checkout@v4
@@ -43,8 +42,8 @@ jobs:
               if: github.event_name == 'release'
               with:
                   registry: ${{ steps.registry.outputs.host }}
-                  username: ${{ github.actor }}
-                  password: ${{ github.token }}
+                  username: ${{ secrets.PACKAGE_PUBLISH_USERNAME }}
+                  password: ${{ secrets.PACKAGE_PUBLISH_TOKEN }}
             - name: Build and publish
               uses: docker/build-push-action@v6
               with: