Bump docker/build-push-action from 5 to 6 (#33)

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

.github/workflows/ci.yaml

@@ -31,7 +31,7 @@ jobs:
           password: ${{ secrets.GITHUB_TOKEN }}
 
       - name: Build and push the TAP server image
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: docker/tap
           push: true
@@ -40,7 +40,7 @@ jobs:
             ghcr.io/lsst-sqre/tap-postgres-service:${{ steps.vars.outputs.tag }}
 
       - name: Build and push the UWS database image
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: docker/uws
           push: true
@@ -49,7 +49,7 @@ jobs:
             ghcr.io/lsst-sqre/tap-postgres-uws:${{ steps.vars.outputs.tag }}
 
       - name: Build and push the mock postgres image
-        uses: docker/build-push-action@v5
+        uses: docker/build-push-action@v6
         with:
           context: docker/cadc-postgresql-dev
           push: true