Add pipeline that's always green, for doc-only PRs (#62509)

* Add pipeline that's always green, for doc-only PRs

* Add comment

Author: wtgodbe

.azure/pipelines/report-green.yml

@@ -0,0 +1,37 @@
+# This CI job only runs on PRs where all other jobs are skipped.
+# This allows Build Analysis to report green. Without this, no jobs would run,
+# causing Build Analysis to hang indefinitely (or until someone commented "ba-g {justification}" on the PR).
+
+# Only run this on PRs
+trigger: none
+# Run for all branches, only on paths that no-op other jobs
+pr:
+  autoCancel: true
+  branches:
+    include:
+    - '*'
+  paths:
+    include:
+    - .devcontainer/*
+    - .github/*
+    - .vscode/*
+    - docs/*
+    - '**/*.md'
+    - LICENSE.TXT
+    - THIRD-PARTY-NOTICES.TXT
+
+# ABG - Always Be Green
+jobs:
+- template: /eng/common/templates/jobs/jobs.yml
+  parameters:
+    enableTelemetry: true
+    helixRepo: dotnet/aspnetcore
+    jobs:
+    - job: Report_Green
+      enableSBOM: false
+      pool:
+        vmImage: ubuntu-22.04
+      steps:
+      - powershell: |
+          exit 0
+        displayName: Exit 0