add simple unit test PR gate

Adds a simple GH action pull request gate for `make test`

Author: jaypipes

.github/workflows/unit-test.yaml

@@ -0,0 +1,25 @@
+name: build-unit-test
+on:
+  # Allow manual trigger
+  workflow_dispatch:
+  pull_request:
+    branches:
+      - main
+    paths:
+      - '**.go'
+      - Makefile
+      - go.mod
+      - go.sum
+
+jobs:
+  build:
+    name: make test
+    runs-on: ubuntu-latest
+    steps:
+      - name: checkout code
+        uses: actions/checkout@v2
+      - uses: actions/setup-go@v2
+        with:
+          go-version: '1.15'
+      - name: make test
+        run: make test