build(deps): bump docker/build-push-action from 4 to 6

Bumps [docker/build-push-action](https://github.com/docker/build-push-action) from 4 to 6.
- [Release notes](https://github.com/docker/build-push-action/releases)
- [Commits](docker/build-push-action@v4...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]>

Author: dependabot[bot]

.github/workflows/reusable-build-and-push.yml

@@ -59,7 +59,7 @@ jobs:
           echo "OUTPUTS=type=docker,dest=/tmp/exploit-db-server.tar" >> $GITHUB_ENV
 
       - name: Build
-        uses: docker/build-push-action@v4
+        uses: docker/build-push-action@v6
         with:
           context: .
           platforms: linux/amd64,linux/arm64