deps: Bump flagsmith-flag-engine to 11.0.0

Engine 11.0.0's only breaking change is dropping Python 3.9 support; it
requires >=3.10 and carries no API changes.

Deliberately NOT marked as a breaking change for this SDK. This client
already dropped Python 3.9 in 814e67e ("deps!: drop Python 3.9 support to
allow urllib3 >=2.7.0", #227) and declares python = ">=3.10,<4", which
shipped in 6.x. Engine 11 therefore imposes no constraint on consumers
that this package does not already impose, so a major bump would signal a
break that does not exist.

Relocked with Poetry 2.x to preserve lock-version 2.1; the diff is the
engine package block and the content-hash only.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: matthewelwell

poetry.lock

@@ -10,7 +10,7 @@ documentation = "https://docs.flagsmith.com"
 packages = [{ include = "flagsmith" }]
 
 [tool.poetry.dependencies]
-flagsmith-flag-engine = "^10.2.0"
+flagsmith-flag-engine = "^11.0.0"
 iso8601 = { version = "^2.1.0", python = "<3.11" }
 python = ">=3.10,<4"
 requests = "^2.32.3"