fix: fix path syntax in build-python.yml

Author: 56kyle

.github/workflows/build-python.yml

@@ -47,7 +47,7 @@ jobs:
       - name: Set up Python
         uses: actions/setup-python@v5
         with:
-          python-version-file: ".github\workflows\.python-version"
+          python-version-file: ".github/workflows/.python-version"
 
       - name: Run package build
         run: uvx nox -s build-python