ci: place os correctly

Author: william-silversmith

.github/workflows/python-package.yml

@@ -13,8 +13,8 @@ jobs:
   build:
     runs-on: ${{ matrix.os }}
     strategy:
-      os: [ubuntu-latest, windows-latest]
       matrix:
+        os: [ubuntu-latest, windows-latest]
         python-version: ["3.9", "3.10", "3.11", "3.12", "3.13"]
 
     steps: