v3: OpenAPI validation issues

[apd-bbrewington]

I ran Spectral locally via:

curl -O https://raw.githubusercontent.com/dbt-labs/dbt-cloud-openapi-spec/c019e7548b0537abe258492c7ddb4590d041847a/openapi-v3.yaml
npm install -g @stoplight/spectral-cli
echo 'extends: ["spectral:oas"]' > .spectral.yaml
spectral lint openapi-v3.yaml --ruleset .spectral.yaml > lint_results.txt

Results summary: ✖ 370 problems (29 errors, 341 warnings, 0 infos, 0 hints)

Full results: lint_results.txt

(Attaching as file: GitHub didn't let me include the text b/c 65536 character limit)

[apd-bbrewington]

Glad to attempt a fix & submit a PR, just wanted to share the issue details along to start

[apd-bbrewington]

Note, the PR I just submitted only addresses the 29 errors. Didn't do anything with the 341 warnings, assuming some of those might have been style choices