Update pyproject.toml

Author: V02460

poetry.lock

@@ -222,9 +222,7 @@ ijson = ">=3.1.4"
 matrix-common = "^1.3.0"
 # We need packaging.verison.Version(...).major added in 20.0.
 packaging = ">=20.0"
-# We support pydantic v1 and pydantic v2 via the pydantic.v1 compat module.
-# See https://github.com/matrix-org/synapse/issues/15858
-pydantic = ">=1.7.4, <3"
+pydantic = "~=2.0"
 
 # This is for building the rust components during "poetry install", which
 # currently ignores the `build-system.requires` directive (c.f.