Update and rename main.yml to gh-pages.yml

.github/workflows/gh-pages.yml

@@ -0,0 +1,27 @@
+name: github pages
+
+on:
+  push:
+    branches:
+      - master
+
+jobs:
+  build-deploy:
+    runs-on: ubuntu-18.04
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Setup mdBook
+        uses: peaceiris/actions-mdbook@v1
+        with:
+          mdbook-version: '0.3.5'
+          # mdbook-version: 'latest'
+
+      - run: mdbook build
+
+      - name: Deploy
+        uses: peaceiris/actions-gh-pages@v2
+        env:
+          ACTIONS_DEPLOY_KEY: ${{ secrets.ACTIONS_DEPLOY_KEY }}
+          PUBLISH_BRANCH: gh-pages
+          PUBLISH_DIR: ./book