add workflow

.github/workflows/js_sdk_ci.yml

@@ -0,0 +1,39 @@
+name: Node.js CI
+
+defaults:
+  run:
+    working-directory: ./client/fluence-js
+
+on:
+  push:
+
+jobs:
+  build:
+
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        node-version: [14.x, 15.x]
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - uses: actions/cache@v2
+        with:
+          path: ~/.npm
+          key: ${{ runner.os }}-node-${{ matrix.node-version }}-${{ hashFiles('**/package-lock.json') }}
+          restore-keys: |
+            ${{ runner.os }}-node-${{ matrix.node-version }}
+
+      - name: Setup Node.js ${{ matrix.node-version }}
+        uses: actions/setup-node@v1
+        with:
+          node-version: ${{ matrix.node-version }}
+
+      - run: npm install
+      - run: npm test
+        env:
+          CI: true
+
+