feat: add simple CI

.github/workflows/ci.yaml

@@ -0,0 +1,39 @@
+name: CI
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  Build:
+    runs-on: ubuntu-latest
+    timeout-minutes: 60
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v2
+
+      - name: Read .nvmrc
+        run: echo ::set-output name=NVMRC::$(cat .nvmrc)
+        id: nvm
+
+      - name: Setup Node.js
+        uses: actions/setup-node@master
+        with:
+          node-version: '${{ steps.nvm.outputs.NVMRC }}'
+
+      - name: Get yarn cache directory path
+        id: yarn-cache-dir-path
+        run: echo "::set-output name=dir::$(yarn cache dir)"
+
+      - uses: actions/cache@v2
+        with:
+          path: ${{ steps.yarn-cache-dir-path.outputs.dir }}
+          key: ${{ runner.os }}-yarn-${{ hashFiles('**/yarn.lock') }}
+          restore-keys: |
+            ${{ runner.os }}-yarn-
+
+      - name: Install dependencies
+        run: (yarn install --nonInteractive --frozen-lockfile --prefer-offline || yarn install --nonInteractive --frozen-lockfile --prefer-offline)
+
+      - name: Build
+        run: yarn build