Support ReadonlyArrays in enum prooperty of the SchemaDefinition

[skrtheboss]

Do you want to request a feature or report a bug?

Feature

What is the current behavior?
Assigning a readonly array to the enum value is not allowed.

import type { SchemaDefinition, DocumentDefinition } from 'mongoose';

enum Color {
    RED = 'red',
    GREEN = 'green',
    BLUE = 'blue'
}

const colors: ReadonlyArray<Color> = [Color.RED, Color.GREEN, Color.BLUE]; 

interface ColorEntity {
    color: Color;
}

const colorEntitySchemaDefinition: SchemaDefinition<DocumentDefinition<ColorEntity>> = {
    color: {
        type: String,
        enum: colors,
        required: true,
    } 
}

What is the expected behavior?

The SchemaDefinition should allow passing ReadonlyArrays for the enum values.

What are the versions of Node.js, Mongoose and MongoDB you are using? Note that "latest" is not a version.

node -v
v14.15.5

mongoose -v
v5.12.9