ci: renrew to use GitHub workflow

Author: tsuyoshicho

.github/workflows/generate.yml

@@ -0,0 +1,46 @@
+name: Generate vim help
+on:
+  push:
+    branches:
+      - master
+  workflow_dispatch:
+  schedule:
+    - cron: '36 20 * * Sat'
+
+jobs:
+  deploy:
+    runs-on: ubuntu-latest
+    steps:
+      - name: checkout master
+        uses: actions/checkout@v2
+        with:
+          path: work
+      - name: Checkout gh-pages
+        uses: actions/checkout@v2
+        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
+          # Create tags
+          make html
+
+          cd ..
+          # install
+          cp work/target/html/doc/*.html target
+      - name: Commit updated master branch
+        uses: EndBug/add-and-commit@v7
+        with:
+          cwd: './target'
+          author_name: '${{ github.actor }}'
+          author_email: '${{ github.actor }}@users.noreply.github.com'
+          message: 'Generated by GitHub workflow ${{ github.run_id }}'
+          branch: gh-pages
+        env:
+          GITHUB_TOKEN: ${{ secrets.VIMDOC_JP_TOKEN }}