Switch from travis to github actions.

Author: ehuss

.github/workflows/deploy.yml

@@ -0,0 +1,24 @@
+name: Deploy
+on:
+  push:
+    branches:
+      - master
+
+jobs:
+  deploy:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+    - name: Install mdbook
+      run: |
+        mkdir mdbook
+        curl -Lf https://github.com/rust-lang/mdBook/releases/download/v0.4.8/mdbook-v0.4.8-x86_64-unknown-linux-gnu.tar.gz | tar -xz --directory=./mdbook
+        echo `pwd`/mdbook >> $GITHUB_PATH
+    - name: Generate Book
+      run: |
+        ./generate-book.sh
+    - name: Deploy GitHub Pages
+      uses: rust-lang/simpleinfra/github-actions/static-websites@master
+      with:
+        deploy_dir: book
+        github_token: "${{ secrets.github_token }}"