Fix: [AzurePipelines] manifest.sh didn't know when it was a stable release

In result, the name of the release was wrong, causing confusing
in tools using the manifest.yaml.

azure-pipelines/templates/release-manifest.yml

@@ -1,3 +1,6 @@
+parameters:
+  IsStableRelease: false
+
 steps:
 - task: DownloadBuildArtifacts@0
   displayName: 'Download all bundles'
@@ -5,6 +8,10 @@ steps:
     downloadType: specific
     itemPattern: 'bundles/*'
     downloadPath: '$(Build.ArtifactStagingDirectory)'
+- ${{ if eq(parameters.IsStableRelease, true) }}:
+  - script: |
+      touch .is_stable
+    displayName: 'Mark as stable release'
 - script: |
     set -ex
     ./azure-pipelines/manifest.sh ../a/bundles/

azure-pipelines/templates/release.yml

@@ -164,6 +164,9 @@ jobs:
   steps:
   - template: release-fetch-source.yml
   - template: release-manifest.yml
+    ${{ if eq(parameters.IsStableRelease, true) }}:
+      parameters:
+        IsStableRelease: true
   - template: release-bundles.yml
     parameters:
       CalculateChecksums: false