ci: run tests also on windows

Author: JanTvrdik

.github/workflows/checks.yml

@@ -28,10 +28,11 @@ jobs:
                 run: composer check
 
     tests:
-        runs-on: ubuntu-latest
+        runs-on: ${{ matrix.os }}
         strategy:
             fail-fast: false
             matrix:
+                os: [ ubuntu-latest, windows-latest ]
                 php-version: [ '7.4', '8.0', '8.1', '8.2', '8.3', '8.4' ]
                 dependency-version: [ prefer-lowest, prefer-stable ]
         steps: