Set up the CI (#7)

Author: katspaugh

.github/workflows/lint.yml

@@ -0,0 +1,9 @@
+name: 'Lint'
+on: [pull_request]
+
+jobs:
+  eslint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: reviewdog/action-eslint

.github/workflows/test.yml

@@ -0,0 +1,9 @@
+name: 'Unit tests'
+on: [pull_request]
+
+jobs:
+  tests:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - uses: mattallty/jest-github-action