Remove unused import

Author: humitos

readthedocs/doc_builder/backends/sphinx.py

@@ -17,7 +17,6 @@
 from django.conf import settings
 from django.template import loader as template_loader
 from django.template.loader import render_to_string
-from packaging.version import Version
 
 from readthedocs.builds import utils as version_utils
 from readthedocs.projects.exceptions import ProjectConfigurationError