refactor: Use future warnings.deprecated decorator

[edgarrmondragon]

• https://peps.python.org/pep-0702/
• https://docs.python.org/3.13/library/warnings.html#warnings.deprecated
• https://typing-extensions.readthedocs.io/en/latest/#typing_extensions.deprecated

---

📚 Documentation preview 📚: https://meltano-sdk--2647.org.readthedocs.build/en/2647/

[codspeed-hq]

CodSpeed Performance Report

Merging #2647 will not alter performance

_{Comparing edgarrmondragon/refactor/future-deprecated-decorator (7a6be32) with main (93a0796)}

Summary

✅ 6 untouched benchmarks

[codecov]

Codecov Report

Attention: Patch coverage is 63.63636% with 4 lines in your changes missing coverage. Please review.

Project coverage is 89.61%. Comparing base (93a0796) to head (7a6be32).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
singer_sdk/authenticators.py	60.00%	1 Missing and 1 partial ⚠️
singer_sdk/connectors/sql.py	66.66%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2647      +/-   ##
==========================================
- Coverage   89.67%   89.61%   -0.07%     
==========================================
  Files          58       58              
  Lines        4854     4861       +7     
  Branches      950      955       +5     
==========================================
+ Hits         4353     4356       +3     
- Misses        350      352       +2     
- Partials      151      153       +2     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.