fix: rollback gmpy2 to 2.1.5 (#3745)

.github/workflows/api-tests.yml

     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.10", "3.11", "3.12"]
+        python-version:
+          - "3.10"
+          - "3.11"
 
     env:
       OPENAI_API_KEY: sk-IamNotARealKeyJustForMockTestKawaiiiiiiiiii

api/requirements.txt

 matplotlib~=3.8.2
 yfinance~=0.2.35
 pydub~=0.25.1
-gmpy2~=2.2.0a1
+gmpy2~=2.1.5
 numexpr~=2.9.0
 duckduckgo-search==5.2.2
 arxiv==2.1.0