Add health.yaml workflow (#851)

* Add `health.yaml` workflow

* Nits

* Remove whitespace

* Update args

Author: mosuem

.github/workflows/health.yaml

@@ -0,0 +1,14 @@
+name: Health
+on:
+  pull_request:
+    branches: [ main ]
+    types: [opened, synchronize, reopened, labeled, unlabeled]
+jobs:
+  health:
+    uses: dart-lang/ecosystem/.github/workflows/health.yaml@main
+    with:
+      coverage_web: true
+      checks: "version,changelog,license,coverage,do-not-submit,breaking"
+      use-flutter: true
+    permissions:
+      pull-requests: write

.github/workflows/post_summaries.yaml

@@ -4,7 +4,8 @@ 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: 
+    workflows:
+      - Health
       - Publish
     types:
       - completed