ci: update to poetry 2

[aryarm]

TODO:

• remove upper bound requirement for poetry-conda
• update poetry-conda, nox-poetry, and poetry-shell in dev-env.yml file and add them to pyproject.toml, except for nox-poetry

[tool.poetry.requires-plugins]
poetry-conda = ">=0.1.4"
poetry-plugin-export = ">=1.9"
poetry-plugin-shell = ">=1.0.1"

• upgrade to poetry 2
• relock lock file with poetry 2
• update to poetry-plugin-export v1.9.0 which resolves make use of locked markers in lock file version 2.1 and thereby avoid dependency walk failed python-poetry/poetry-plugin-export#286
• add locked dependencies for all versions of Python to lock file. Make sure they're pep517 compatible due to remove the setup reader python-poetry/poetry#9099

[aryarm]

this code should not be merged yet. The poetry.lock file no longer contains the minimum versions of our dependencies :(

my goal is for the min versions to remain in the lock file and for these versions to be present for all versions > 3.10:

    "matplotlib==3.10.0 ; python_version >= '3.10'",
    "numpy==2.2.2 ; python_version >= '3.10'",
    "pandas==2.2.3 ; python_version >= '3.10'",
    "pysam==0.22.1 ; python_version >= '3.10'",
    "scikit-learn==1.6.1 ; python_version >= '3.10'",
    "scipy==1.15.1 ; python_version >= '3.10'",
    "statsmodels==0.14.4 ; python_version >= '3.10'",
    "pyfaidx==0.8.1.3 ; python_version >= '3.10'",
    "pgenlib==0.92.0 ; python_version >= '3.10'",

we might need cjolowicz/nox-poetry#663 for that to work