ci: use default vim

Author: tsuyoshicho

.github/workflows/generate.yml

@@ -20,11 +20,6 @@ jobs:
         with:
           path: target
           ref: gh-pages
-      - name: Setup Vim
-        uses: thinca/action-setup-vim@v1
-        with:
-          vim_version: 'v8.2.0020'
-          vim_type: 'Vim'
       - name: Generate new document
         run: |
           cd work