chore(deps): upgrading oas to v6

[erunion]

🧰 What's being changed?

Upgrades us to v6 of the oas library which included some breaking changes for how data was stored within the Operation class that oas/tooling exposes.

📖 Release Notes

6.1.0 (2020-11-12)

• feat: adding some new methods to the operation class (fix: Stop nesting Markdown response descriptions in a p tag #311) (c7b6fbc), closes #311

6.0.0 (2020-11-10)

BREAKING CHANGE

If you are using oas/tooling the internal storage within the Operation class has been changed to no longer override the internal scope of itself. Operation data within that class is now stored within a schema property.

And if you aren't using oas/tooling, carry on!

• feat: adding a new hasRequestBody method to the operation (feature/refresh-logs-on-try-it #310) (c467472), closes #310
• refactor: pull change how schema is stored in the operation class (Bump @babel/core from 7.4.4 to 7.6.0 #301) (83ddd52), closes #301
• chore(deps-dev): bump @readme/eslint-config from 3.6.2 to 3.6.3 (Bump webpack-merge from 4.1.1 to 4.2.2 #303) (551efc7), closes #303
• chore(deps-dev): bump conventional-changelog-cli from 2.1.0 to 2.1.1 (Bump react-test-renderer from 16.8.6 to 16.9.0 #304) (c34a95c), closes #304
• chore(deps-dev): bump eslint from 7.12.1 to 7.13.0 (ReadMe Flavored Markdown #306) (719874d), closes #306
• chore(deps-dev): bump jest from 26.6.1 to 26.6.3 (Bump js-cookie from 2.1.4 to 2.2.1 #305) (2c3387d), closes #305
• chore(deps): bump actions/checkout from v2.3.3 to v2.3.4 (Removing some unused dependencies from the API Explorer. #308) (71640d4), closes #308

[erunion]

I'd add a hasResponses method into oas but since responses are required to be present to be a valid OAS definition I don't think it makes sense to add to account for legacy specs in our DB that might not be valid.