ci(github): init Gthub actions

Author: madeindjs

.github/workflows/main.yml

@@ -0,0 +1,19 @@
+# .github/workflows/main.yml
+# Copy/pasted from https://angular.io/guide/testing#configure-project-for-github-actions
+name: CI Nest.js app through Github Actions
+on: push
+jobs:
+  unit-test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Use Node.js 16.x
+        uses: actions/setup-node@v1
+        with:
+          node-version: 16.x
+
+      - name: Setup
+        run: npm ci
+
+      - name: Test
+        run: npm test