ci: add basic Rust CI

.github/workflows/swhkd.yml

@@ -0,0 +1,22 @@
+name: swhkd
+
+on:
+  push:
+  pull_request:
+
+env:
+  CARGO_TERM_COLOR: always
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+    - name: Checkout
+      uses: actions/checkout@v2
+
+    - name: Build
+      run: cargo build --verbose
+
+    - name: Run tests
+      run: cargo test --verbose