feat: Upgrade the pydantic from v1 to V2 by shuchu · Pull Request #3942 · feast-dev/feast

What this PR does / why we need it:
Based on the requirements from the Feast users, we want to upgrade the Pydantic version to v2 (2.6) for the performance of Feast.

Here are a few important package version changes:
pydantic >= 2.0.0
great_expectations>=0.15.41 (the upper bound is removed. Its required by the pydantic v2.)

Since it changes many files in the codebase, I humbly ask our reviewers to review this PR carefully.

Which issue(s) this PR fixes:
Fixes #3778