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

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

[codspeed-hq[bot]]

CodSpeed Performance Report

Merging #2647 will not alter performance

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

Summary

✅ 6 untouched benchmarks

[codecov[bot]]

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 :warning:
singer_sdk/connectors/sql.py	66.66%	1 Missing and 1 partial :warning:

Additional details and impacted files

```diff @@ 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 ```

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