ci: migrate to GitHub actions

.github/workflows/build.yml

@@ -0,0 +1,23 @@
+name: build
+
+on: [push, pull_request]
+
+env:
+  FORCE_COLOR: 3
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v1
+        with:
+          node-version: 14
+      - run: yarn --frozen-lockfile
+      # - run: yarn prettier-check
+      - run: yarn tslint
+      - run: yarn typecheck
+      - run: yarn build
+      - run: yarn cover
+      - run: yarn nyc report --reporter json
+      - run: 'bash <(curl -s https://codecov.io/bash)'