add workflow for PRs

Author: chenasraf

.github/workflows/pull_requests.yml

@@ -0,0 +1,18 @@
+name: Releases
+
+on:
+  pull_request:
+    branches:
+      - main
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    if: "!contains(github.event.head_commit.message, '[skip ci]')"
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions/setup-node@v1
+        with:
+          node-version: "12.x"
+      - run: yarn install --frozen-lockfile
+      - run: yarn test
+      - run: yarn build