fix: Don't crash when a null is in an enum (fixes #500). Thanks @juspence!#501

dbanty merged 2 commits intomainopenapi-generators/openapi-python-client:mainfrom

500-dont-crash-on-null-enum-valueopenapi-generators/openapi-python-client:500-dont-crash-on-null-enum-valueCopy head branch name to clipboard