Update auto-pr for prerel-8.2

.github/workflows/auto-pr.yml

@@ -1,4 +1,4 @@
-name: Merge branch dev with rel-8.1
+name: Merge branch prerel-8.2 with rel-8.1
 on:
   push:
     branches:
@@ -7,7 +7,7 @@ permissions:
   contents: read
 
 jobs:
-  merge-dev-with-rel-8-1:
+  merge-prerel-8-2-with-rel-8-1:
     permissions:
       contents: write  # for peter-evans/create-pull-request to create branch
       pull-requests: write  # for peter-evans/create-pull-request to create a PR
@@ -15,7 +15,7 @@ jobs:
     steps:
       - uses: actions/checkout@v2
         with:
-          ref: dev
+          ref: prerel-8.2
       - name: Reset promotion branch
         run: |
           git fetch origin rel-8.1:rel-8.1
@@ -24,8 +24,8 @@ jobs:
         uses: peter-evans/create-pull-request@v3
         with:
           branch: auto-merge/rel-8-1/${{github.run_number}}
-          title: Merge branch dev with rel-8.1
-          body: This PR generated automatically to merge dev with rel-8.1. Please review the changed files before merging to prevent any errors that may occur.
+          title: Merge branch prerel-8.2 with rel-8.1
+          body: This PR generated automatically to merge prerel-8.2 with rel-8.1. Please review the changed files before merging to prevent any errors that may occur.
           reviewers: maliming
           token: ${{ github.token }}
       - name: Merge Pull Request