Bump docker/build-push-action from 4 to 5

Bumps [docker/build-push-action](https://github.com/docker/build-push-action) from 4 to 5.
- [Release notes](https://github.com/docker/build-push-action/releases)
- [Commits](docker/build-push-action@v4...v5)

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

Signed-off-by: dependabot[bot] <[email protected]>

.github/workflows/container.yml

@@ -66,7 +66,7 @@ jobs:
       # this only builds the amd64 version of the image, which is fine as that's
       # all that is needed to test the container on GitHub Actions' build servers (which are running amd64 CPUs)
       - name: Build container image to test
-        uses: docker/build-push-action@v4
+        uses: docker/build-push-action@v5
         with:
           load: true # this is important, as this tells build-push-action to save the container to the local docker daemon
           build-args: |
@@ -103,7 +103,7 @@ jobs:
       # won't be rebuilt since the local docker daemon has that still cached
       - name: Push container image to registry
         if: inputs.do_upload
-        uses: docker/build-push-action@v4
+        uses: docker/build-push-action@v5
         with:
           platforms: linux/amd64,linux/arm/v7,linux/arm64/v8,linux/ppc64le,linux/s390x
           push: true