Remove incorrect @classmethod on constructors

[avandecreme]

This confuses ty:

error[invalid-argument-type]: Argument to bound method `PrivateKey.__new__` is incorrect
   --> conftest.py:118:12
    |
118 |     return PrivateKey(private_key)
    |            ^^^^^^^^^^^^^^^^^^^^^^^ Expected `str`, found `<class 'PrivateKey'>`
    |
info: Method defined here
   --> .venv/lib/python3.13/site-packages/biscuit_auth/__init__.pyi:512:9
    |
512 |     def __new__(cls, data: str) -> PrivateKey: ...
    |         ^^^^^^^ --- Parameter declared here
    |

error[too-many-positional-arguments]: Too many positional arguments to bound method `PrivateKey.__new__`: expected 1, got 2
   --> conftest.py:118:23
    |
118 |     return PrivateKey(private_key)
    |                       ^^^^^^^^^^^
    |
info: Method signature here
   --> .venv/lib/python3.13/site-packages/biscuit_auth/__init__.pyi:512:9
    |
512 |     def __new__(cls, data: str) -> PrivateKey: ...
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |

[divarvel]

the tests fail because of python version update. main now support 3.14, so you could try rebasing

[divarvel]

Cool! You'll just need to sign the eclipse DCO (not a CLA). Instructions should be in CONTRIBUTING.md

[avandecreme]

Done. (The process was infuriating though)

[divarvel]

Done. (The process was infuriating though)

thank you. yeah it’s tedious. Thankfully it’s a one-time thing (and necessary to have the legal enforcement provided by the eclipse foundation)

[avandecreme]

Thanks for merging!