`set_tags` missing from python SDK

According to **unified-api** page, each SDK should have a `set_tags` method.

https://develop.sentry.dev/sdk/unified-api/

![image](https://user-images.githubusercontent.com/20026896/154281816-4282aac2-7ca5-4add-8fcf-0b8864866c22.png)
 
I found it was dicscussed and implemented 2 years ago in this PR #530 but the PR was closed.

Can this feature be added?

Thanks


