Implement initial CI.

Author: peterhuene

.github/workflows/main.yml

@@ -0,0 +1,36 @@
+name: CI
+on:
+  push:
+    branches:
+      - main
+    tags: ['[0-9]*']
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  test:
+    name: Run tests
+    runs-on: ${{ matrix.os }}
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+    steps:
+    - uses: actions/checkout@v3
+    - name: Install Rust
+      run: |
+        rustup update stable --no-self-update
+        rustup default stable
+      shell: bash
+    - name: Run all tests
+      run: cargo test --all
+
+  rustfmt:
+    name: Format source code
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v3
+    - name: Install Rust
+      run: rustup update stable && rustup default stable && rustup component add rustfmt
+    - name: Run `cargo fmt`
+      run: cargo fmt -- --check