using templates in release-branch-build.yml

Author: aminya

script/vsts/release-branch-build.yml

@@ -39,10 +39,7 @@ jobs:
       IsSignedZipBranch: $[ dependencies.GetReleaseVersion.outputs['Version.IsSignedZipBranch'] ]
 
     steps:
-      - task: NodeTool@0
-        inputs:
-          versionSpec: 12.4.0
-        displayName: Install Node.js 12.4.0
+      - template: platforms/templates/preparation.yml
 
       # This has to be done separately because VSTS inexplicably
       # exits the script block after `npm install` completes.