Update CI

* Update drone to v1.x
* Add GitHub Actions

.github/workflows/ci.yaml

@@ -0,0 +1,18 @@
+on:
+  push:
+  pull_request:
+
+name: CI
+
+jobs:
+  build:
+    name: Build GitBook
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@master
+        with:
+          fetch-depth: 2
+      - name: Build
+        uses: docker://yeasy/docker_practice
+        with:
+          args: build