Default value of Enum type

Description

I'm trying to provide a default value for a generated class that uses an enum. Currently type enum is always defaulted to INVALID_VALUE_OPENAPI_GENERATED, despite the field default being specified. Is this a bug?

I have tried experimenting with the mustache templates to output the default with {{{defaultValue}}} for the specified enum, where I could then modify the templates to provide the default, however this variable is always empty for this use case.

openapi-generator version

5.3.0 C++ Pistache. - I am not sure if this is specific to the C++ Pistache Generator.

Command line used for generation

Example snippet from .yaml definition:

..
Codec:
    type: string
    example: JPEG
    default: JPEG
    enum:
        - JPEG
        - PNG
..

Steps to reproduce

1. prepare a .yaml which contains the above class
2. generate the code with the C++ Pistache generator

Notice that the header of the generated code contains the following:
Codec::eCodec m_value = Codec::eCodec::INVALID_VALUE_OPENAPI_GENERATED;

I would expect the code would be:
Codec::eCodec m_value = Codec::eCodec::JPEG;

Reproduce the supplied YAML with the C++ Pistache generator, then trace how enum defaults reach the Mustache templates and generated header. Done means a field with default: JPEG initializes to Codec::eCodec::JPEG instead of INVALID_VALUE_OPENAPI_GENERATED.