Bump docker/build-push-action from 2 to 6

Bumps [docker/build-push-action](https://github.com/docker/build-push-action) from 2 to 6.
- [Release notes](https://github.com/docker/build-push-action/releases)
- [Commits](docker/build-push-action@v2...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]>

.github/workflows/amphora_builder.yaml

@@ -25,7 +25,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - name: Build Docker Image
-        uses: docker/build-push-action@v2
+        uses: docker/build-push-action@v6
         with:
           context: ./amphora-image-builder
           push: false