build(deps): bump docker/build-push-action from 5 to 6 (#6964)

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>
Co-authored-by: Paulin Todev <[email protected]>

.github/workflows/check-linux-build-image.yml

@@ -19,7 +19,7 @@ jobs:
         uses: docker/setup-buildx-action@v3
 
       - name: Create test Linux build image
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: ./build-image
           push: false
@@ -28,7 +28,7 @@ jobs:
             GO_RUNTIME=golang:1.22.5-bullseye
 
       - name: Create test Linux build image for boring crypto
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: ./build-image
           push: false