Update gunicorn requirement from >=22.0 to >=25.3.0

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Updates the requirements on gunicorn to permit the latest version.

Release notes

Sourced from gunicorn's releases.

Gunicorn 25.3.0

Bug Fixes

• HTTP/2 ASGI Body Duplication: Fix request body being received twice in HTTP/2 ASGI requests, causing JSON parsing errors with "Extra data" messages (#3558)

• ASGI Chunked EOF Handling: Add finish() method to callback parser to handle chunked encoding edge case where connection closes before final CRLF after zero-chunk

• HTTP/2 Documentation: Fix http_protocols examples to use comma-separated string instead of list syntax (#3561)

• Chunked Encoding: Reject chunk extensions containing bare CR bytes per RFC 9112 (#3556)

• Request Line Limit: Fix --limit-request-line 0 to mean unlimited as documented, instead of using default maximum. Works with both Python and fast C parser. (#3563)

Security

• ASGI Parser Header Validation: Add security checks per RFC 9110/9112:
  • Reject duplicate Content-Length headers
  • Reject requests with both Content-Length and Transfer-Encoding
  • Reject chunked transfer encoding in HTTP/1.0
  • Reject stacked chunked encoding
  • Validate Transfer-Encoding values
  • Strict chunk size validation

Changes

• Fast HTTP Parser: Update to gunicorn_h1c >= 0.6.3 for asgi_headers property and InvalidChunkExtension validation for bare CR rejection

• ASGI PROXY Protocol: Add PROXY protocol v1/v2 support to callback parser

• Docker Images: Update to Python 3.14

Commits

• 9bce72c Update changelog with missing 25.3.0 changes
• 2a15fdb Fix pylint isinstance-second-argument-not-valid-type warning
• 8d08aaa Fix --limit-request-line 0 to mean unlimited
• d40a374 Fix pytest-asyncio configuration and treq_asgi hex escapes
• da8bd48 Remove unused AsyncRequest class
• b00f125 Integrate gunicorn_h1c 0.6.3 with InvalidChunkExtension support
• bdb2ebd Reject chunk extensions with bare CR bytes (RFC 9112)
• 7057fc9 Fix http_protocols documentation to use string syntax
• d43acb8 Update to gunicorn_h1c >= 0.6.2 for asgi_headers support
• cbd27e8 Merge pull request #3559 from benleembruggen/fix/http2-asgi-body-duplication
• Additional commits viewable in compare view

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