httpcore 0.15.0 support

[tbhi]

https://github.com/encode/httpcore/releases/tag/0.15.0 was released recently but setup.py has httpcore>=0.14.5,<0.15.0 - can this be bumped?

[michaeloliverx]

This would unblock #2096

[lovelydinosaur]

Addressed in #2214 yup. (Which is waiting for review)

[michaeloliverx]

Should we try and get #2096 in too or wait till another release?

[lovelydinosaur]

Not sure - do you want to try to get the test suite passing against that pull request first?

[michaeloliverx]

All green now buddy ✅