use the post_summaries workflow when publishing (#180)

.github/workflows/post_summaries.yaml

@@ -0,0 +1,19 @@
+# A CI configuration to post comments to PRs.
+#
+# This workflow will have permissions to create comments on the PR even if the
+# original workflow couldn't.
+
+name: Comment on the pull request
+
+on:
+  workflow_run:
+    workflows: 
+      - Publish
+    types:
+      - completed
+
+jobs:
+  upload:
+    uses: dart-lang/ecosystem/.github/workflows/post_summaries.yaml@main
+    permissions:
+      pull-requests: write

.github/workflows/publish.yaml

@@ -12,6 +12,5 @@ jobs:
   publish:
     if: ${{ github.repository_owner == 'dart-lang' }}
     uses: dart-lang/ecosystem/.github/workflows/publish.yaml@main
-    permissions:
-      id-token: write # Required for authentication using OIDC
-      pull-requests: write # Required for writing the pull request note
+    with:
+      write-comments: false