Do you have a plan to drop python < 3.7

Hey there,
I tried to find any discussion about it in your issues, but didn't find.

The reason why maybe we should do it:
1. python < 3.7 are not maintained anymore.
2. and some of libraries like `wheel` stops to support deprecated pythons.

https://github.com/pypa/virtualenv/blob/ebbccecdb65725025dfc8f4af504d7de3a770e95/src/virtualenv/seed/wheels/embed/__init__.py#L40