feat: adding support for OpenAPI 3.1

[erunion]

Building off of the work that @LoicBoursin started in https://github.com/APIDevTools/swagger-parser/pull/171 this also:

• Replaces z-schema with Ajv because it fully supports 2020-12/Draft 7 out of the box.
  • Check out [this comment[(https://github.com/APIDevTools/swagger-parser/pull/171#pullrequestreview-679813725) for some conversation about this.
  • Additionally, swapping for Ajv also fixed the x-properties issue that was called out here.
• Updates the amount of real-world APIs that are being loaded from https://apis.guru to be tested against.
• Fixes a handful of 3.1-related bugs and incompatibilities.
• Cleans up the real-world definitions list to remove exclusions that no longer apply, add some new ones, and alphabetize the list so it's tidier.
• Gets all tests passing.
• I've also reverted the lockFileVersion: 2 change to package-lock.json in https://github.com/APIDevTools/swagger-parser/pull/171 to make this overall diff a little cleaner.

All told with this work this library now fully supports OpenAPI 3.1.

[philsturgeon]

Thank you @erunion !

[crutch12]

@philsturgeon are you going to release it? Last release was in August 2021

[simplesmiler]

Seems to have landed in 10.1.0.