Feature support adding version_limitations <=, >= for repository

Hi.

I have a remote repository which is a proxy of pypi.org. I am trying to control more about packages versions. I am only able to find to use the exclude patterns.

However for use case like below, the exclude patterns will not be a good implementation.

Example:

For package markupsafe, I only wants to provide "version_limits": ">=0.18,<2.1.0", because newer versions will have break changes.

It is very common for users to set packages versions by >-=, <= inside their requirements3.txt for pip install.

I image it will also be very common for version control within a range, like >= or <=.