Bump docker/build-push-action from 5 to 6 (#466)

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/ci.yaml

@@ -75,7 +75,7 @@ jobs:
 
     - name: Build and push Docker image with tag master # only on pushes to keikoproj/upgrade-manager
       if: github.event_name == 'push' && github.repository == 'keikoproj/upgrade-manager'
-      uses: docker/build-push-action@v5
+      uses: docker/build-push-action@v6
       with:
         context: .
         file: ./Dockerfile
@@ -85,7 +85,7 @@ jobs:
 
     - name: Build and push Docker image with tag latest # only on releases of keikoproj/upgrade-manager
       if: github.event_name == 'release' && github.repository == 'keikoproj/upgrade-manager'
-      uses: docker/build-push-action@v5
+      uses: docker/build-push-action@v6
       with:
         context: .
         file: ./Dockerfile
@@ -95,7 +95,7 @@ jobs:
 
     - name: Build and push Docker image with tag git-tag # only on releases of keikoproj/upgrade-manager
       if: github.event_name == 'release' && github.repository == 'keikoproj/upgrade-manager'
-      uses: docker/build-push-action@v5
+      uses: docker/build-push-action@v6
       with:
         context: .
         file: ./Dockerfile