Adding GitHub action

Adds GitHub action.

.github/workflows/go.yml

@@ -0,0 +1,20 @@
+name: Go
+
+on:
+  - push
+  - pull_request
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v2
+
+    - name: Set up Go
+      uses: actions/setup-go@v2
+
+    - name: Build
+      run: make
+
+    - name: Test
+      run: make test