Update gunicorn requirement from >=23.0.0 to >=26.0.0

[dependabot]

Updates the requirements on gunicorn to permit the latest version.

Release notes

Sourced from gunicorn's releases.

26.0.0

Breaking Changes

• Eventlet worker removed: The eventlet worker class has been dropped. Migrate to gevent, gthread, or tornado.

New Features

• ASGI Framework Compatibility Suite: New end-to-end compatibility test harness covering Starlette, FastAPI, Litestar, Quart, Sanic, and BlackSheep. Current grid passes 438/444 tests (98%).
• ASGI Test Suite Expansion: 134 additional ASGI unit tests covering protocol semantics, lifespan, websockets, and chunked framing.

Security

• HTTP/1.1 Request-Target Validation (RFC 9112 sections 3.2.3, 3.2.4):
  • Reject authority-form request-target outside CONNECT
  • Reject asterisk-form request-target outside OPTIONS
  • Reject relative-reference request-targets
• Header Field Hardening (RFC 9110):
  • Reject control characters in header field-value (section 5.5)
  • Reject forbidden trailer field-names (section 6.5.1)
  • Reject Content-Length list form (RFC 9112 section 6.3)
• Request Smuggling Hardening:
  • Tighten keepalive gate and scope finish_body byte cap
  • Keep _body_receiver alive across the keepalive smuggling gate so pipelined requests cannot re-enter a closed body
  • Address parser/protocol findings from a six-point WSGI/ASGI audit
• PROXY Protocol (ASGI): Enforce proxy_allow_ips and tighten v1/v2 parsing in the ASGI callback parser.
• Connection Draining: Drain the connection on close per RFC 9112 section 9.6 to prevent reset-on-close truncation.

Bug Fixes

• Body Framing on HEAD/204/304:
  • Keep Content-Length on HEAD and 304 responses (#3621)
  • Drop body framing on HEAD/204/304 even when the framework set it
  • Warn once when an ASGI app emits a body for a no-body response
• HTTP/2 ASGI:
  • Fix _handle_stream_ended to set _body_complete in the async HTTP/2 handler so request bodies finalize correctly on stream end
  • Add InvalidChunkExtension mapping and fast-parser support in ASGI tests (#3565)
• HTTP/1.1 100-Continue: Stop adding Transfer-Encoding: chunked to 100-Continue interim responses.
• WebSocket Close Handshake (RFC 6455):
  • Comply with the close handshake state machine
  • Close the transport after the close handshake completes
  • Fix binary send when the text key is None
• Early Hints: Validate headers in the early_hints callback to match process_headers; pass only the header name to InvalidHeader (#3588).
• ASGI Framework Fixes:
  • Fix ASGI disconnect handling for Django-style apps
  • Fix Litestar request handling (use raw ASGI receive for body/headers)
  • Fix Litestar HTTP endpoints for compatibility tests
  • Fix Quart headers endpoint to normalize keys to lowercase
  • Fix Quart WebSocket close test app (missing accept())
  • Fix duplicate Transfer-Encoding header for BlackSheep streaming

... (truncated)

Commits

• 5d819cf release: 26.0.0
• b45c70d Merge pull request #3611 from zc-mattcen/docs-typo
• 99c8d48 Merge pull request #3623 from benoitc/chore/drop-eventlet-add-h2-uvloop-test-...
• 5a655af Merge pull request #3622 from benoitc/test/docker-port-and-ipv4-fixes
• 201df19 chore: remove eventlet worker; add h2 and uvloop to test deps
• f4ac8e1 test: pass action name to dirty client and stabilize after TTOU spam
• 54d38af test: unblock docker fixtures on macOS hosts
• 68843c8 Merge pull request #3621 from benoitc/fix/asgi-preserve-content-length-on-hea...
• 31f2618 Merge pull request #3620 from benoitc/fix/asgi-proxy-protocol-trust-and-parsing
• 41ec752 fix: keep Content-Length on HEAD and 304 responses
• Additional commits viewable in compare view

[pip-install-python]

Closing per the network's dependabot policy: this is a floor-raise on a range requirement. Floors encode minimum-compatibility knowledge (the gunicorn floor IS the CVE fact); the resolver already installs the latest release under them, and raising the floor erases that meaning while adding none. Security updates are unaffected — they arrive through GitHub's separate security-update channel. Floor moves happen deliberately via the template's sync specs, every encoding at once.

— 2plot-network ops seat (dependabot-triage)

[dependabot]

OK, I won't notify you again about this release, but will get in touch when a new version is available. If you'd rather skip all updates until the next major or minor version, let me know by commenting @dependabot ignore this major version or @dependabot ignore this minor version. You can also ignore all major, minor, or patch releases for a dependency by adding an ignore condition with the desired update_types to your config file.

If you change your mind, just re-open this PR and I'll resolve any conflicts on it.