fix languagetool runner setup

Author: haya14busa

Diff for: .github/workflows/reviewdog.yml

@@ -24,6 +24,11 @@ jobs:
           reporter: github-check
           level: warning
 
+  languagetool:
+    name: runner / languagetool
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
       - uses: reviewdog/action-languagetool@v1
         with:
           github_token: ${{ secrets.github_token }}