Run CI on Windows + Linux

.github/workflows/build.yml

@@ -4,7 +4,11 @@ on: [push, pull_request]
 
 jobs:
   build:
-    runs-on: windows-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [windows-latest, ubuntu-latest]
+    runs-on: ${{ matrix.os }}
     steps:
     - uses: actions/checkout@v3
     - name: Cache pip