feat: emit ::notice:: upgrade link when breaking changes found

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: reuvenharrison

README.md

@@ -158,7 +158,7 @@ Each **Review** link opens a hosted page with a side-by-side spec diff and **App
 |---|---|---|---|
 | `base` | — (required) | Path to the base (old) OpenAPI spec | file path, URL, git ref |
 | `revision` | — (required) | Path to the revised (new) OpenAPI spec | file path, URL, git ref |
-| `oasdiff-token` | — (required) | oasdiff API token — [sign up at oasdiff.com](https://oasdiff.com) | — |
+| `oasdiff-token` | — (required) | oasdiff API token — [get one at oasdiff.com/pricing](https://oasdiff.com/pricing) | — |
 | `github-token` | `${{ github.token }}` | GitHub token for posting the PR comment; requires `pull-requests: write`, `statuses: write` | — |
 | `include-path-params` | `false` | Include path parameter names in endpoint matching | `true`, `false` |
 | `exclude-elements` | `''` | Exclude certain kinds of changes from the output | `endpoints`, `request`, `response` (comma-separated) |

breaking/Dockerfile

@@ -1,4 +1,5 @@
 FROM tufin/oasdiff:stable
+RUN apk add --no-cache jq
 ENV PLATFORM github-action
 COPY entrypoint.sh /entrypoint.sh
 ENTRYPOINT ["/entrypoint.sh"]

breaking/entrypoint.sh

@@ -101,6 +101,16 @@ echo "breaking<<$delimiter" >>"$GITHUB_OUTPUT"
 
 if [ -n "$breaking_changes" ]; then
     write_output "$(echo "$breaking_changes" | head -n 1)" "$breaking_changes"
+    # Emit upgrade notice pointing to the free review page
+    urlencode() { printf '%s' "$1" | jq -sRr @uri; }
+    base_path=$(echo "$base" | sed 's/.*://')
+    rev_path=$(echo "$revision" | sed 's/.*://')
+    owner="${GITHUB_REPOSITORY%%/*}"
+    repo="${GITHUB_REPOSITORY#*/}"
+    head_sha=$(jq -r '.pull_request.head.sha // empty' "$GITHUB_EVENT_PATH" 2>/dev/null || echo "")
+    if [ -z "$head_sha" ]; then head_sha="$GITHUB_SHA"; fi
+    free_review_url="https://www.oasdiff.com/review?owner=${owner}&repo=${repo}&base_sha=$(urlencode "$GITHUB_BASE_REF")&rev_sha=${head_sha}&base_file=$(urlencode "$base_path")&rev_file=$(urlencode "$rev_path")"
+    echo "::notice::📋 Review & approve these breaking changes → ${free_review_url}"
 else
     write_output "No breaking changes"
 fi