Pydantic >= 2.0 compatibility

[SarahG-579462]

Overview

Related Issue / discussion

Pydantic >= 2.0 offers legacy 1.0 support by importing pydantic.v1. Let's use this to allow support for both versions of pydantic, while waiting for the debian fix: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1052028

Additional information

Dependency policy (RFC2)

• I have ensured that this PR meets RFC2 requirements

Updates to public demo

• I have ensured that breaking changes to the pygeoapi master demo server have been addressed
  • https://github.com/geopython/demo.pygeoapi.io/blob/master/services/pygeoapi_master/local.config.yml

Contributions and licensing

(as per https://github.com/geopython/pygeoapi/blob/master/CONTRIBUTING.md#contributions-and-licensing)

• I'd like to contribute [feature X|bugfix Y|docs|something else] to pygeoapi. I confirm that my contributions to pygeoapi will be compatible with the pygeoapi license guidelines at the time of contribution
• I have already previously agreed to the pygeoapi Contributions and Licensing Guidelines

[aulemahal]

Nice!