Update GitHub Actions workflows. (#554)

This PR was automatically generated by the
update-workflows-ecosystem-providers workflow in the pulumi/ci-mgmt
repo, from commit e5045b810db34310235bbe1a83d3c3758995e790.

.github/workflows/build.yml

@@ -1,6 +1,6 @@
 # WARNING: This file is autogenerated - changes will be overwritten if not made via https://github.com/pulumi/ci-mgmt
 
-name: build
+name: main # For consistency with bridged providers.
 on:
   push:
     branches:
@@ -351,6 +351,25 @@ jobs:
         author_name: Failure while building SDKs
         fields: repo,commit,author,action
         status: ${{ job.status }}
+
+  tag_release_if_labeled_needs_release:
+    name: Tag release if labeled as needs-release
+    needs: publish
+    runs-on: ubuntu-latest
+    steps:
+    - name: check if this commit needs release
+      if: ${{ env.RELEASE_BOT_ENDPOINT != '' }}
+      uses: pulumi/action-release-by-pr-label@main
+      with:
+        command: "release-if-needed"
+        repo: ${{ github.repository }}
+        commit: ${{ github.sha }}
+        slack_channel: ${{ secrets.RELEASE_OPS_SLACK_CHANNEL }}
+      env:
+        RELEASE_BOT_ENDPOINT: ${{ secrets.RELEASE_BOT_ENDPOINT }}
+        RELEASE_BOT_KEY: ${{ secrets.RELEASE_BOT_KEY }}
+        GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+
   test:
     runs-on: pulumi-ubuntu-8core
     needs: