ci: add GitHub Actions test workflow

.github/workflows/test.yml

@@ -0,0 +1,16 @@
+name: Test
+on:
+  push:
+    branches: [master]
+  pull_request:
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-go@v5
+        with:
+          go-version-file: go.mod
+      - run: go test -race ./...
+      - run: go vet ./...
+      - run: go build ./...