ci: add build and test workflow for core

.github/workflows/ci.yml

@@ -0,0 +1,34 @@
+name: CI
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    paths:
+    - '**.zig'
+    - '**.zon'
+    - '**.c'
+    - '**.h'
+
+jobs:
+  build:
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+    runs-on: ${{ matrix.os }}
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          submodules: false
+
+      - uses: mlugg/setup-zig@v2
+
+      - name: Build
+        run: zig build
+
+      - name: Test
+        run: |
+          zig build test -Doptimize=Debug
+          zig build test -Doptimize=ReleaseFast