test other OSs

Author: bengl

.github/workflows/ci.yml

@@ -6,7 +6,10 @@ env:
 jobs:
   test:
     name: Test & Lint
-    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        os: [ubuntu-latest, macos-latest, windows-latest]
+    runs-on: ${{ matrix.os }}
     steps:
       - name: Checkout
         uses: actions/checkout@v2