ci: Don't try to push container images from dependabot PRs.

Author: jnms-me

.github/workflows/docker-pr.yml

@@ -25,7 +25,7 @@ jobs:
         with:
           context: .
           file: Dockerfile.production
-          push: true
+          push: ${{ github.triggering_actor != 'dependabot[bot]' }}
           tags: |
             ghcr.io/zeuswpi/tab:pr-${{ github.event.pull_request.number }}
             ghcr.io/zeuswpi/tab:pr-${{ github.event.pull_request.number }}-${{ github.sha }}