feat(src/djinit/templates/project): bump target-version to py313

Why: enable support for Python 3.13.

New Features
- Updated pyproject.toml template to target Python 3.13, allowing builds with newer interpreters.

Enhancements
- Improves compatibility with upcoming Python releases.

src/djinit/templates/project/pyproject.toml-tpl

@@ -28,7 +28,7 @@ dependencies = [
 
 [tool.ruff]
 line-length = 88
-target-version = "py38"
+target-version = "py313"
 
 [tool.ruff.lint]
 select = [