Install script/vsts dependencies on release branch

Author: aminya

script/vsts/platforms/templates/preparation.yml

@@ -32,9 +32,8 @@ steps:
     inputs:
       versionSpec: '3.8'
 
-  # Windows Specific
-  - script: |
-      cd script\vsts
+  - pwsh: |
+      cd script/vsts
       npm install
-    displayName: Install script/vsts dependencies on Windows
-    condition: eq(variables['Agent.OS'], 'Windows_NT')
+    displayName: Install script/vsts dependencies
+    condition: or(eq(variables['Agent.OS'], 'Windows_NT'), eq(variables['IsReleaseBranch'], 'true'))