week_2: pin pydantic>=2.4.0 to avoid v2 ReDoS advisory (CodeRabbit #925)

GHSA pydantic ReDoS affects >=2.0.0,<2.4.0; first patched in 2.4.0.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: PRAteek-singHWY

requirements.txt

@@ -63,7 +63,7 @@ pyasn1
 pyasn1-modules
 pycodestyle
 pycparser
-pydantic>=2,<3
+pydantic>=2.4.0,<3
 pyee
 pyflakes
 PyGithub