Bump docker/build-push-action from v1 to v2.2.2

Bumps [docker/build-push-action](https://github.com/docker/build-push-action) from v1 to v2.2.2.
- [Release notes](https://github.com/docker/build-push-action/releases)
- [Commits](https://github.com/docker/build-push-action/compare/v1...4a531fa5a603bab87dfa56578bd82b28508c9547)

Signed-off-by: dependabot[bot] <support@github.com>

.github/workflows/release.yml

@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
-      - uses: docker/build-push-action@v1
+      - uses: docker/build-push-action@v2.2.2
         with:
           dockerfile: server/Dockerfile
           username: ${{ secrets.DOCKER_USERNAME }}
@@ -22,7 +22,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
-      - uses: docker/build-push-action@v1
+      - uses: docker/build-push-action@v2.2.2
         with:
           dockerfile: wikibase/Dockerfile
           username: ${{ secrets.DOCKER_USERNAME }}