ci: Bump docker/build-push-action from 3 to 4 (#133)

Bumps [docker/build-push-action](https://github.com/docker/build-push-action) from 3 to 4.
- [Release notes](https://github.com/docker/build-push-action/releases)
- [Commits](docker/build-push-action@v3...v4)

---
updated-dependencies:
- dependency-name: docker/build-push-action
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.github/workflows/build.yml

@@ -71,16 +71,16 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v3
       - name: Build UI
-        uses: docker/build-push-action@v3
+        uses: docker/build-push-action@v4
         with:
           context: opendc-web/opendc-web-ui
           file: opendc-web/opendc-web-ui/Dockerfile
       - name: Build Web Server
-        uses: docker/build-push-action@v3
+        uses: docker/build-push-action@v4
         with:
           file: opendc-web/opendc-web-server/Dockerfile
       - name: Build Runner
-        uses: docker/build-push-action@v3
+        uses: docker/build-push-action@v4
         with:
           file: opendc-web/opendc-web-runner/Dockerfile
   build-docs:

.github/workflows/publish.yml

@@ -25,7 +25,7 @@ jobs:
           username: ${{ secrets.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}
       - name: Push to Docker Hub
-        uses: docker/build-push-action@v3
+        uses: docker/build-push-action@v4
         with:
           push: true
           file: opendc-web/opendc-web-runner/Dockerfile
@@ -49,7 +49,7 @@ jobs:
           username: ${{ secrets.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}
       - name: Push to Docker Hub
-        uses: docker/build-push-action@v3
+        uses: docker/build-push-action@v4
         with:
           push: true
           file: opendc-web/opendc-web-server/Dockerfile
@@ -75,7 +75,7 @@ jobs:
           username: ${{ secrets.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}
       - name: Push to Docker Hub
-        uses: docker/build-push-action@v3
+        uses: docker/build-push-action@v4
         with:
           push: true
           context: opendc-web/opendc-web-ui