Relax pydantic upper bound to <3.0 #3

Problem

aind-data-schema restricts pydantic to >=2.7, <2.12. The upper bound was added
because of a regression in pydantic 2.12 around model_validators, but AllenNeuralDynamics/aind-data-schema#1583 fixed that.
So the constraint seems to have outlived the bug.

Proposal

Relax the bound to pydantic>=2.7, <3.0.

To catch this kind of breakage before downstream users do, you can test both ends of the declared range in CI using uv's --resolution strategies:

strategy:
  matrix:
    resolution: ["lowest-direct", "highest"]

steps:
  - uses: astral-sh/setup-uv@v5
  - run: uv pip install -e .[dev] --resolution ${{ matrix.resolution }} --system
  - run: coverage run -m unittest discover && coverage report

highest catches new releases (like pydantic 2.12) the day they ship. You can run it on a schedule and it fails here first, instead of in downstream projects. lowest-direct verifies the >=2.7 floor still actually works. uv pip install is a drop-in replacement for the current pip install -e .[dev] step, so existing test/lint commands run unchanged.

Happy to open a PR for either piece.