add lint-diff call to lint task

.github/workflows/push_tests.yml

@@ -15,10 +15,19 @@ jobs:
         uses: actions/setup-python@v1
         with:
           python-version: 3.7
+      - name: Node cache
+        uses: actions/cache@v1
+        with:
+          path: ~/.npm
+          key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}
+          restore-keys: |
+            ${{ runner.os }}-node-
       - name: Lint with flake8
         run: |
           pip install flake8
-          make lint
+      - name: Lint diff with eslint
+        run: |
+          cd client && make lint-diff
 
   unit-test:
     runs-on: ubuntu-latest