Fix httpx._types.VerifyTypes type hint

[ondrg]

httpx removes VerifyTypes in 0.28.0 (encode/httpx@8e36f2b)

Raises error:

aioxmlrpc/client.py:156: in ServerProxy
    context: Optional[httpx._types.VerifyTypes] = None,
E   AttributeError: module 'httpx._types' has no attribute 'VerifyTypes'

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.33%. Comparing base (a04221b) to head (dfb0c00).
Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #33      +/-   ##
==========================================
+ Coverage   97.29%   97.33%   +0.03%     
==========================================
  Files           2        2              
  Lines          74       75       +1     
==========================================
+ Hits           72       73       +1     
  Misses          2        2              

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[mardiros]

I should have release a version that freeze httpx to <0.28 until I fix that.

Thanks for the MR !