Fix/issue 164 objects

[uguraka]

This PR addresses Issue #164 by enabling objects with sequence representation in analysis functions.

Changes made:

1. Updated _bytes() in primer3/thermoanalysis.pyx to accept any object that implements __str__, not just str or bytes.
2. Updated calc_tm() in primer3/thermoanalysis.pyx to explicitly convert non-bytes objects to string before validation to prevent TypeError.
3. Updated type hints in primer3/bindings.py to reflect that objects are now accepted.
4. Added test cases in tests/test_issue_164.py covering both (calc_tm) and (calc_end_stability) paths.

Verification:

• Added tests/test_issue_164.py passes successfully.
• Existing logic for str and bytes remains unchanged.

[benpruitt]

lgtm; thanks for pulling this together. A couple of minor requests:

1. Can you add a module docstring to your tests module, conformant w/ the module docstring used in other test modules (https://github.com/libnano/primer3-py/tree/master/tests)?
2. Rename the test module with a more directly descriptive name (e.g., test_str_rep_ifc_compat.py

Once we have this PR buttoned up, I'll spin a minor version release (we've got a couple of changes sitting on master that have yet to be incorporated into a release, all minor).

[uguraka]

Hello, I have renamed the test module and added the docstring.

[benpruitt]

@uguraka thanks for your work on this feature -- we cut v2.3.0 today, which includes this merged PR, and it is now live on PyPI.

[uguraka]

Happy to have contributed! Thank you for the review and for getting this released so quickly.