upgrade to Python 3.13 (#43)

Author: alexrashed

.github/workflows/build.yml

@@ -42,6 +42,8 @@ jobs:
 
       - name: Setup Python
         uses: actions/setup-python@v6
+        with:
+          python-version-file: .python-version
 
       # Add a retry to avoid issues when this action is running
       # right after the package is published on PyPi

.python-version

@@ -1 +1 @@
-3.11
+3.13