Replace the task-list-completed GitHub app with a GitHub action

.github/workflows/continuous-integration.yml

@@ -10,6 +10,8 @@ on:
       - synchronize
       - edited
 
+permissions: {}
+
 jobs:
   ci:
     name: changed files

.github/workflows/manual-sync.yml

@@ -14,6 +14,9 @@ on:
         required: true
         default: "false"
 
+permissions:
+  contents: write
+
 jobs:
   sync:
     name: Execute Sync Task

.github/workflows/task-list-checker.yml

@@ -0,0 +1,20 @@
+name: GitHub Task List Checker
+on:
+  pull_request:
+    branches:
+      - master
+    types:
+      - opened
+      - reopened
+      - synchronize
+      - edited
+permissions:
+  statuses: write
+jobs:
+  task-list-checker:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check for incomplete task list items
+        uses: Shopify/task-list-checker@main
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/welcome-new-contributors.yml

@@ -4,6 +4,9 @@ on:
   pull_request_target:
     types: [opened]
 
+permissions:
+  pull-requests: write
+
 jobs:
   welcome-new-contributor:
     runs-on: ubuntu-latest