Merge pull request moby#5127 from crazy-max/ci-update-docs-upstream

ci(docs-upstream): missing path for frontend rules docs

Author: tonistiigi

.github/workflows/docs-upstream.yml

@@ -18,13 +18,15 @@ on:
       - 'docs/attestations/slsa-definitions.md'
       - 'docs/attestations/attestation-storage.md'
       - 'frontend/dockerfile/docs/reference.md'
+      - 'frontend/dockerfile/docs/rules/**'
   pull_request:
     paths:
       - '.github/workflows/docs-upstream.yml'
       - 'docs/buildkitd.toml.md'
       - 'docs/attestations/slsa-definitions.md'
       - 'docs/attestations/attestation-storage.md'
       - 'frontend/dockerfile/docs/reference.md'
+      - 'frontend/dockerfile/docs/rules/**'
 
 jobs:
   validate: