ci: add github actions config

.github/workflows/main.yml

@@ -0,0 +1,40 @@
+name: Nightly
+
+on:
+  push:
+    paths:
+      - "**.zig"
+    branches:
+      - main
+  schedule:
+    - cron: "0 0 * * *"
+  workflow_dispatch:
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: goto-bus-stop/setup-zig@v2
+        with:
+          version: master
+      - uses: actions/checkout@v3
+      - run: zig fmt src/*.zig
+  test:
+    strategy:
+      matrix:
+        os: [ubuntu-latest, windows-latest, macos-latest]
+    runs-on: ${{matrix.os}}
+    steps:
+      - uses: goto-bus-stop/setup-zig@v2
+        with:
+          version: master
+      - uses: actions/checkout@v3
+      - run: zig build test
+  bench:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: goto-bus-stop/setup-zig@v2
+        with:
+          version: master
+      - uses: actions/checkout@v3
+      - run: zig build -Doptimize=ReleaseFast -Dcpu=baseline bench