Switch to Pydantic v1 namespace and allow Pydantic v1 or v2

[josephgruber-umbra]

What I am changing

This change incorporates the use of the Pydantic v1 namespace which was introduced in Pydantic 1.10.17 and all 2.x versions. This allows the use of Pydantic v1 while also supporting either Pydantic >=1.10.17,<3. The goal being to allow users of this package a planned upgrade path to Pydantic 2.x instead of an abrupt switch.

See #166 for more on this issue

How I did it

• Changed the Pydantic dependency to >1.10.18 (latest) and <3 (all 2.x versions)
• Changing all Pydantic import statements to use the v1 namespace (e.g. from pydantic.v1 import ...)

How you can test it

• Verified all existing unit tests pass
• Verified existing functionality works as expected on private services

Reference

See the Pydantic migration guide which was updated to reference the new v1 namespace support back in August: https://docs.pydantic.dev/latest/migration/#continue-using-pydantic-v1-features