{CI} Add PR title check (#11982)

azure-pipelines.yml

@@ -8,6 +8,20 @@ trigger:
     - '*'
 
 jobs:
+- job: CheckPullRequestTitle
+  displayName: "Check the Format of Pull Request Title"
+  condition: and(succeeded(), in(variables['System.PullRequest.TargetBranch'], 'dev', 'release'))
+
+  pool:
+    vmImage: 'ubuntu-16.04'
+  steps:
+    - bash: |
+        echo "Check Title of Pull Request: #$(System.PullRequest.PullRequestNumber)"
+        title=$(curl https://api.github.com/repos/Azure/azure-cli/pulls/$(System.PullRequest.PullRequestNumber) | jq -r '.title')
+        [[ $title =~ ^(\[.*\]|\{.*\}).* ]] && exit 0
+        echo "Pull Request title should follow https://aka.ms/submitAzPR"
+        exit 1
+
 - job: RejectPullRequestToMasterBranch
   displayName: "Reject Pull Request To Master Branch"
   condition: and(succeeded(), eq(variables['System.PullRequest.TargetBranch'], 'master'))