Add PR Health workflow (#3736)

* Add PR Health workflow

* Ignore licenses for generated files

Author: mosuem

.github/workflows/health.yaml

@@ -0,0 +1,14 @@
+name: Health
+on:
+  pull_request:
+    branches: [ master ]
+    types: [opened, synchronize, reopened, labeled, unlabeled]
+
+jobs:
+  health:
+    uses: dart-lang/ecosystem/.github/workflows/health.yaml@main
+    with:
+      ignore_license: "**.g.dart"
+      sdk: dev
+    permissions:
+      pull-requests: write

.github/workflows/post_summaries.yaml

@@ -0,0 +1,17 @@
+name: Comment on the pull request
+
+on:
+  # Trigger this workflow after the Health workflow completes. This workflow will have permissions to
+  # do things like create comments on the PR, even if the original workflow couldn't.
+  workflow_run:
+    workflows: 
+      - Health
+      - Publish
+    types:
+      - completed
+
+jobs:
+  upload:
+    uses: dart-lang/ecosystem/.github/workflows/post_summaries.yaml@main
+    permissions:
+      pull-requests: write

.github/workflows/publish.yaml

@@ -14,6 +14,7 @@ jobs:
     if: ${{ github.repository_owner == 'dart-lang' }}
     uses: dart-lang/ecosystem/.github/workflows/publish.yaml@main
     with:
+      write-comments: false
       # Protected github deployment environment, requires approval to publish.
       environment: pub.dev
       sdk: dev