Bump docker/build-push-action from 5 to 6 (#388)

Bumps [docker/build-push-action](https://github.com/docker/build-push-action) from 5 to 6.
- [Release notes](https://github.com/docker/build-push-action/releases)
- [Commits](docker/build-push-action@v5...v6)

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

.github/workflows/docker.yml

@@ -82,7 +82,7 @@ jobs:
             org.oxidize-rb.ruby.platform=${{ matrix.platform.ruby_target }}
 
       - name: Docker build
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           builder: ${{ steps.buildx.outputs.name }}
           context: ./docker
@@ -156,7 +156,7 @@ jobs:
             --highestUserWastedPercent "$highest_user_wasted_percent"
 
       - name: Docker push
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           builder: ${{ steps.buildx.outputs.name }}
           context: ./docker

.github/workflows/integration.yml

@@ -106,7 +106,7 @@ jobs:
           cat Gemfile.issue
 
       - name: Build and push Docker image
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: .
           file: ./Dockerfile.issue