Use Python 3.13 for pydantic matrix, since only pydantic 2.12 supports

Python 3.14

Author: bryantpark04

.circleci/config.yml

@@ -121,7 +121,7 @@ workflows:
           name: pydantic-<< matrix.pydantic_version >>
           matrix:
             parameters:
-              python_version: ["3.14"]
+              python_version: ["3.13"]
               pydantic_version: ["2.6", "2.7", "2.8", "2.9", "2.10", "2.11", "2.12"]
               httpx_version: ["0.28"]
       - test: