Update virtualenv from 20.24.2 to 21.7.8

Author: pyup-bot

requirements.txt

@@ -26,4 +26,4 @@ pyyaml==6.0.1 ; python_version >= "3.10" and python_version < "4.0"
 requests==2.31.0 ; python_version >= "3.10" and python_version < "4.0"
 tomli==2.0.1 ; python_version >= "3.10" and python_version < "3.11"
 urllib3==2.0.4 ; python_version >= "3.10" and python_version < "4.0"
-virtualenv==20.24.2 ; python_version >= "3.10" and python_version < "4.0"
+virtualenv==21.7.8; python_version >= "3.10" and python_version < "4.0"