{CI} Update GitHub workflows to use ubuntu-latest (Azure#8528)

Author: wangzelin007

.github/workflows/AddIssueComment.yml

@@ -4,7 +4,7 @@ on:
 
 jobs:
   thank-user:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     permissions:
       issues: write
     name: Say thanks for the Issue

.github/workflows/AddIssueCommentWithLabel.yml

@@ -6,7 +6,7 @@ on:
 jobs:
   comment-non-security:
     if: contains(github.event.issue.labels.*.name, 'non-security')
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     permissions:
       issues: write
     name: Comment on issue