chore: replace manual list with reference

Author: 56kyle

{{cookiecutter.project_name}}/pyproject.toml

@@ -16,7 +16,7 @@ classifiers = [
     "Operating System :: OS Independent",
     "Programming Language :: Python :: 3",
     "Programming Language :: Python :: 3 :: Only",
-{%- for version in ["3.10", "3.11"] %}
+{%- for version in {{cookiecutter.python_versions}} %}
     "Programming Language :: Python :: {{ version }}",
 {%- endfor %}
     "{{ cookiecutter.development_status }}"