Add generation name rule

Author: wyunchi-ms

.azure-pipelines/powershell-core.yml

@@ -12,7 +12,7 @@ variables:
   TestTarget: Test
   Configuration: Debug
   DebugLocalBuildTasks: true
-  IsGenerateBased: $[eq(variables['system.pullRequest.targetBranch'], 'generation')]
+  IsGenerateBased: $[startsWith(variables['system.pullRequest.targetBranch'], 'generation')]
   BuildTimeoutInMinutes: 120
   AnalysisTimeoutInMinutes: 120
   TestTimeoutInMinutes: 180