feat(ci): switch from travis to github actions

.github/workflows/github-pages.yml

@@ -0,0 +1,20 @@
+name: GitHub Pages
+
+on:
+  push
+
+jobs:
+  publish:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v1
+      - run: npm install
+      - run: npx hexo algolia
+        env:
+          HEXO_ALGOLIA_INDEXING_KEY: ${{ secrets.HEXO_ALGOLIA_INDEXING_KEY }}
+      - run: npx hexo g
+      - uses: peaceiris/actions-gh-pages@v3
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          publish_dir: ./public