Add auto approval for auto merge (#68)

The auto merge process needs two reviews to meet Project Mu branch
protection policy requirements. This change auto approves dependency
update pull requests so they can be auto merged.

Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>

Author: makubacki

.github/workflows/AutoMerger.yml

@@ -13,6 +13,27 @@ on:
   workflow_call:
 
 jobs:
+  bot_approval:
+    name: Bot Approval
+    if: |
+      github.event_name == 'pull_request_target' &&
+      (github.event.action == 'opened' || github.event.action == 'reopened') &&
+      (github.event.pull_request.user.login == 'dependabot[bot]' || github.event.pull_request.user.login == 'uefibot')
+    runs-on: ubuntu-latest
+    permissions:
+      pull-requests: write
+
+    steps:
+      - uses: hmarr/auto-approve-action@v3
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          review-message: "🤖 auto approved a ${{ github.event.pull_request.user.login }} PR."
+
+      - uses: hmarr/auto-approve-action@v3
+        with:
+          github-token: ${{ secrets.PROJECT_MU_BOT_TOKEN }}
+          review-message: "🤖 auto approved a ${{ github.event.pull_request.user.login }} PR."
+
   auto_merge:
     name: Merge
     runs-on: ubuntu-latest
@@ -28,13 +49,14 @@ jobs:
         id: auto_merge
         uses: pascalgn/automerge-action@v0.15.5
         env:
-          GITHUB_TOKEN: "${{ secrets.GITHUB_TOKEN }}"
+          GITHUB_TOKEN: "${{ secrets.PROJECT_MU_BOT_TOKEN }}"
+          MERGE_ERROR_FAIL: "false"     # Do not fail if an auto merge couldn't happen
           MERGE_FILTER_AUTHOR: "${{ matrix.author }}"
           MERGE_FORKS: "false"          # dependabot and uefibot come from local repo branches - forks not needed
           MERGE_LABELS: "!state:duplicate,!state:invalid,!state:needs-maintainer-feedback,!state:needs-submitter-info,!state:under-discussion,!state:wont-fix,!type:notes,!type:question"
           MERGE_METHOD: "squash"        # Default merge method squash (instead of "merge")
           MERGE_REMOVE_LABELS: = ""     # Do not remove any labels from a PR after merge
-          MERGE_REQUIRED_APPROVALS: "0" # Auto merge these PRs without human reviewers involved (need to pass PR gates)
+          MERGE_REQUIRED_APPROVALS: "2" # Two PRs can be humans or bots (need to pass PR gates)
           MERGE_RETRIES: "6"            # Check if PR status checks pass up to 6 times
           MERGE_RETRY_SLEEP: "10000"    # Check if PR status checks are met every 10 secs (6 * 10 = check over 1 min)
           UPDATE_LABELS: ""             # Always update these PRs if needed to merge

.sync/workflows/leaf/auto-merge.yml

@@ -38,4 +38,10 @@ on:
 
 jobs:
   merge_check:
+    if: |
+      ((github.event_name == 'pull_request_target' || github.event_name == 'pull_request_review') &&
+       (github.event.pull_request.user.login == 'dependabot[bot]' || github.event.pull_request.user.login == 'uefibot')) ||
+      ((github.event_name == 'check_suite') &&
+       (github.event.check_suite.sender.login == 'dependabot[bot]' || github.event.check_suite.sender.login == 'uefibot'))
     uses: microsoft/mu_devops/.github/workflows/AutoMerger.yml@{{ sync_version.mu_devops }}
+    secrets: inherit