Update Danger setup to run via Buildkite + Add RuboCop linter (#627)

Author: mokagio

.buildkite/pipeline.yml

@@ -63,3 +63,22 @@ steps:
     plugins: [*docker_plugin]
     agents:
       queue: "default"
+
+  - group: "Linters"
+    steps:
+      - label: ☢️ Danger - PR Check
+        command: danger
+        key: danger
+        if: build.pull_request.id != null
+        retry:
+          manual:
+            permit_on_passed: true
+        agents:
+          queue: linter
+
+      - label: ":rubocop: Rubocop"
+        command: rubocop
+        key: rubocop
+        if: build.pull_request.id != null
+        agents:
+          queue: linter

.github/workflows/run-danger.yml

@@ -1,13 +1,18 @@
-name: ☢️ Danger
+name: ☢️ Trigger Danger On Buildkite
 
 on:
   pull_request:
-    types: [opened, reopened, ready_for_review, synchronize, edited, review_requested, review_request_removed, labeled, unlabeled, milestoned, demilestoned]
+    types: [labeled, unlabeled, milestoned, demilestoned, ready_for_review, review_requested, review_request_removed]
 
 jobs:
   dangermattic:
-    # runs on draft PRs only for opened / synchronize events
-    if: ${{ (github.event.pull_request.draft == false) || (github.event.pull_request.draft == true && contains(fromJSON('["opened", "synchronize"]'), github.event.action)) }}
-    uses: Automattic/dangermattic/.github/workflows/reusable-run-danger.yml@v1.0.0
+    if: ${{ (github.event.pull_request.draft == false) }}
+    uses: Automattic/dangermattic/.github/workflows/reusable-retry-buildkite-step-on-events.yml@v1
+    with:
+      org-slug: automattic
+      pipeline-slug: release-toolkit
+      retry-step-key: danger
+      build-commit-sha: ${{ github.event.pull_request.head.sha }}
+      cancel-running-github-jobs: false
     secrets:
-      github-token: ${{ secrets.DANGERMATTIC_GITHUB_TOKEN }}
+      buildkite-api-token: ${{ secrets.TRIGGER_BK_BUILD_TOKEN }}