ci: switch to GitHub Actions

Author: ark120202

.github/workflows/ci.yml

@@ -0,0 +1,15 @@
+name: CI
+
+on: [push, pull_request]
+
+jobs:
+  main:
+    name: Main
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v1
+      - uses: actions/setup-node@v1
+      - run: yarn --frozen-lockfile
+      - run: yarn build
+      - run: yarn lint