ci: update global workflows (#532)

.github/workflows/autoupdate-labeler.yml

@@ -0,0 +1,50 @@
+---
+# This action is centrally managed in https://github.com/<organization>/.github/
+# Don't make changes to this file in this repo as they will be overwritten with changes made to the same file in
+# the above-mentioned repo.
+
+name: Label PR autoupdate
+
+on:
+  pull_request:
+    types:
+      - edited
+      - opened
+
+jobs:
+  label_pr:
+    if: >-
+      startsWith(github.repository, 'LizardByte/') &&
+      contains(github.event.pull_request.body, fromJSON('"] I want maintainers to keep my branch updated\r"'))
+    runs-on: ubuntu-latest
+    steps:
+      - name: Label autoupdate
+        if: >-
+          contains(github.event.pull_request.body,
+            fromJSON('"\n- [x] I want maintainers to keep my branch updated\r"')) == true
+        uses: actions/github-script@v6
+        with:
+          github-token: ${{ secrets.GH_BOT_TOKEN }}
+          script: |
+            github.rest.issues.addLabels({
+              issue_number: context.issue.number,
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              labels: ['autoupdate']
+            })
+
+      - name: Unlabel autoupdate
+        if: >-
+          contains(github.event.pull_request.body,
+            fromJSON('"\n- [x] I want maintainers to keep my branch updated\r"')) == false &&
+          contains(github.event.pull_request.labels.*.name, 'autoupdate')
+        uses: actions/github-script@v6
+        with:
+          github-token: ${{ secrets.GH_BOT_TOKEN }}
+          script: |
+            github.rest.issues.removeLabel({
+              issue_number: context.issue.number,
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              name: ['autoupdate']
+            })