Enable new httpx versions

[dirkkul]

proxies got removed in 0.28.0 and replaced with a combination of proxy (single proxy) and mounts (multi proxy). I just replaced everything with mounts. Minimum version with proxy is 0.26 which is now our new minimum version.

[orca-security-eu]

Orca Security Scan Summary

Status	Check	Issues by priority
Passed	Infrastructure as Code	0   0   0   0	View in Orca
Passed	Secrets	0   0   0   0	View in Orca
Passed	Vulnerabilities	0   0   0   0	View in Orca

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 83.33333% with 1 line in your changes missing coverage. Please review.

Project coverage is 91.93%. Comparing base (1efb556) to head (210b510).

Files with missing lines	Patch %	Lines
weaviate/connect/authentication_async.py	50.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1474      +/-   ##
==========================================
- Coverage   92.00%   91.93%   -0.08%     
==========================================
  Files         174      174              
  Lines       14912    14910       -2     
==========================================
- Hits        13720    13707      -13     
- Misses       1192     1203      +11     

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