add GitHub action on pushing to run lint (#224)

* Add script to run eslint for the project

* Add GitHub Action for linting

Prevent merges with linting errors

* Rename GitHub Action "build_push" to "build_push_master"

.github/workflows/build_push_all.yml

@@ -0,0 +1,11 @@
+name: Lint
+on: push
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Install modules
+        run: yarn
+      - name: Run ESLint
+        run: yarn lint