httpx v0.28 update breaks proxy functionality

[sonnivs]

Describe the bug
In the latest version of httpx (0.28.0), the deprecated proxies argument was removed. Scholarly currently relies on this argument, causing it to break when httpx is updated beyond version 0.27.2 with the following error message:

TypeError: Client.__init__() got an unexpected keyword argument 'proxies'

To Reproduce

from scholarly import ProxyGenerator

pg = ProxyGenerator()
pg.FreeProxies()

Expected behavior
The library should work as expected, ideally regardless of the installed httpx version or as a quick fix with the pinned httpx version.

Desktop (please complete the following information):

• Proxy service: FreeProxies
• python version: 3.10
• OS: Ubuntu
• Version 1.7.11

Do you plan on contributing?
Your response below will clarify whether the maintainers can expect you to fix the bug you reported.

• Yes, I will create a Pull Request with the bugfix.

I don't have the time currently but could try if there is no fix within a few weeks.

Additional context
Currently, a workaround is to pin httpx to version 0.27.2.