Disable pushing container images from forks (#207)

* Try disabling pushing container images from forks

* Skip attest step from forks

* Add changelog

Author: bouweandela

.github/workflows/containers.yaml

@@ -43,12 +43,13 @@ jobs:
           cache-to: type=gha,mode=max
           context: .
           file: packages/ref/Dockerfile
-          push: true
+          push: ${{ ! github.event.pull_request.head.repo.fork }}
           sbom: true
           tags: ${{ steps.metadata.outputs.tags }}
           labels: ${{ steps.metadata.outputs.labels }}
       - name: Attest to REF image
         uses: actions/attest-build-provenance@v2
+        if: ${{ ! github.event.pull_request.head.repo.fork }}
         with:
           subject-name: ghcr.io/${{ github.repository_owner }}/ref
           subject-digest: ${{ steps.push.outputs.digest }}

changelog/207.ci.md

@@ -0,0 +1 @@
+Disabled trying to push container images to the registry from forks.