run CI on Windows and macOS as well as Linux

.github/workflows/ci.yml

@@ -3,7 +3,11 @@ on: [push, pull_request]
 
 jobs:
   unit-test:
-    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+      fail-fast: true
+    runs-on: ${{ matrix.os }}
     env:
       CARGO_TERM_COLOR: always
     steps:
@@ -15,6 +19,9 @@ jobs:
           override: true
       - uses: Swatinem/rust-cache@v1
       - run: cargo test -- --skip src/lib.rs
+        if: ${{ matrix.os != 'windows-latest' }}
+      - run: cargo test -- --skip src\lib.rs
+        if: ${{ matrix.os == 'windows-latest' }}
   lint:
     runs-on: ubuntu-latest
     env: