Remove gmpy2 2.1 pin

[whoami730]

Fixes #40901

📝 Checklist

• The title is concise and informative.
• The description explains in detail what this PR is about.
• I have linked a relevant issue or discussion.
• I have updated the documentation and checked the documentation preview.

⌛ Dependencies

[tobiasdiez]

Thanks a lot for the PR!

The update of the env files is currently not working (due to some known issues in some pkg versions). This would require #39189 first (ready for review!). Alternatively, we could just use something like >= 2.1.5 (I actually don't know what would be the necessary lower bound)

[whoami730]

Alternatively, we could just use something like >= 2.1.5 (I actually don't know what would be the necessary lower bound)

Right, we can do that. That will effectively make it so that we don't need to update the env files and avoid dependence on #39189