Add a basic Makefile and CI workflow for GitHub

.github/workflows/ci.yml

@@ -0,0 +1,27 @@
+name: CI
+
+on:
+  pull_request:
+    branches: [main]
+  push:
+    branches: [main]
+
+jobs:
+  test:
+    name: "Test"
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+      with:
+        fetch-depth: 0
+    - uses: actions/setup-go@v4
+      with:
+        go-version: '1.20.x'
+    - uses: actions/cache@v3
+      with:
+        path: ~/go/pkg/mod
+        key: ${{ runner.os }}-go-${{ hashFiles('**/go.sum') }}
+        restore-keys: |
+          ${{ runner.os }}-go-
+    - name: Run tests
+      run: make test

Makefile

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+.PHONY: test
+test:
+	# test all packages
+	go test -parallel 8 ./...