Add github action for ESLint (#1125)

* add github lint action

* use yaml instructions from action repo

* fix source root var

* fix source root var

* remove source root var

* install libusb

* use forked action

* remove libusb setup from action vm

* use new version of lint action

* Fix version tag of action

* update workflow file

* update workflow file

.github/workflows/lint.yml

@@ -0,0 +1,14 @@
+name: Lint
+on: pull_request
+
+jobs:
+  eslint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: gnosis/safe-react-eslint-action@main
+        # GITHUB_TOKEN in forked repositories is read-only
+        # https://help.github.com/en/actions/reference/events-that-trigger-workflows#pull-request-event-pull_request
+        if: ${{ github.event_name == 'push' || github.event.pull_request.head.repo.full_name == github.repository }}
+        with:
+          repo-token: ${{secrets.GITHUB_TOKEN}}