From the openapi spec:
https://spec.openapis.org/oas/latest.html#fixed-fields-7
each endpoint needs to have an `operationId`:
> Unique string used to identify the operation. The id MUST be unique
> among all operations described in the API. The operationId value is
> case-sensitive. Tools and libraries MAY use the operationId to uniquely
> identify an operation, therefore, it is RECOMMENDED to follow common
> programming naming conventions.
Running the linter on our openapi.json file with this command:
`npx @redocly/openapi-cli lint openapi.json`
produced the following warning on all of our endpoints:
> Operation object should contain `operationId` field
This commit resolves these warnings by adding an operationId field to
each endpoint.
`nullable` is no longer a valid type, and types also can't be an empty
string, so just bringing a number of issues with types in compliance
with the openapi spec.
