Ignore case when evaluating enums

[vordimous]

Is your feature request related to a problem? Please describe.
providing the sasl.mechanism: SCRAM-SHA-256 throws an error that the mechanism is invalid and must be scram-sha-256.

Describe the solution you'd like
Handle different cases for enums like sasl.mechanism: SCRAM-SHA-256

[vordimous]

enum validation is handled by the json schema and this issue will resolve itself when there are clearer error messages #1122