CI: add autobump workflow (#145518)

.github/workflows/autobump.yml

@@ -0,0 +1,40 @@
+name: Bump casks on schedule or request
+
+on:
+  workflow_dispatch:
+    inputs:
+      casks:
+        description: Custom list of casks to livecheck and bump if outdated
+        required: false
+  schedule:
+    # Every day at 5am
+    - cron: "0 5 * * *"
+
+env:
+  CASKS: >
+    google-chrome
+    firefox
+
+permissions:
+  contents: read
+
+jobs:
+  autobump:
+    if: github.repository == 'Homebrew/homebrew-cask'
+    runs-on: macos-latest
+    steps:
+      - name: Set up Homebrew
+        id: set-up-homebrew
+        uses: Homebrew/actions/setup-homebrew@master
+
+      - name: Configure Git user
+        uses: Homebrew/actions/git-user-config@master
+        with:
+          username: ${{ (github.event_name == 'workflow_dispatch' && github.actor) || 'BrewTestBot' }}
+
+      - name: Bump casks
+        uses: Homebrew/actions/bump-packages@master
+        continue-on-error: true
+        with:
+          token: ${{ secrets.HOMEBREW_CASKS_REPO_WORKFLOW_TOKEN }}
+          casks: ${{ github.event.inputs.casks || env.CASKS }}