Add Actionlint

Author: alexeyr

.github/actionlint-matcher.json

@@ -0,0 +1,17 @@
+{
+  "problemMatcher": [
+    {
+      "owner": "actionlint",
+      "pattern": [
+        {
+          "regexp": "^(?:\\x1b\\[\\d+m)?(.+?)(?:\\x1b\\[\\d+m)*:(?:\\x1b\\[\\d+m)*(\\d+)(?:\\x1b\\[\\d+m)*:(?:\\x1b\\[\\d+m)*(\\d+)(?:\\x1b\\[\\d+m)*: (?:\\x1b\\[\\d+m)*(.+?)(?:\\x1b\\[\\d+m)* \\[(.+?)\\]$",
+          "file": 1,
+          "line": 2,
+          "column": 3,
+          "message": 4,
+          "code": 5
+        }
+      ]
+    }
+  ]
+}

.github/workflows/lint-js-and-ruby.yml

@@ -65,3 +65,14 @@ jobs:
       run: yarn start format.listDifferent
     - name: Type-check TypeScript
       run: yarn run type-check
+    - name: Lint GitHub Actions
+      # We only download and run Actionlint if there is any difference in GitHub Action workflows
+      # https://github.com/rhysd/actionlint/blob/main/docs/usage.md#on-github-actions
+      run: |
+        git fetch origin ${{ github.event.pull_request.base.sha }}
+        if git diff --name-only ${{ github.event.pull_request.base.sha }} ${{ github.sha }} | grep -q '^.github/workflows'; then
+          echo "::add-matcher::.github/actionlint-matcher.json"
+          bash <(curl https://raw.githubusercontent.com/rhysd/actionlint/main/scripts/download-actionlint.bash)
+          SHELLCHECK_OPTS="-S warning" ./actionlint -color
+        fi
+      shell: bash