ci: add GitHub Actions CI (go vet + tests)

Author: Urethramancer

.github/workflows/ci.yml

@@ -0,0 +1,23 @@
+name: CI
+
+on:
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up Go
+        uses: actions/setup-go@v4
+        with:
+          go-version: '1.21'
+      - name: Install dependencies
+        run: go mod download
+      - name: Run vet
+        run: go vet ./...
+      - name: Run tests
+        run: go test ./...