Bug in enum keys generation: underscores should not be removed if enum value contains digits. E. g. for value `AMAZON_S3` generated key `AMAZONS3` is wrong

[nicky1038]

For example, this enum definition

[
    //...
    "foo.bar.StorageType": {
      "description": "this enum contains available object storages",
      "type": "string",
      "default": "ORACLE_OBJECT_STORAGE",
      "enum": [
        "ORACLE_OBJECT_STORAGE",
        "AMAZON_S3",
      ]
    },
    //...
]

is transformed into

export enum FooBarStorageTypeDto {
  ORACLE_OBJECT_STORAGE = "ORACLE_OBJECT_STORAGE",
  AMAZONS3 = "AMAZON_S3",
}

Please notice AMAZONS3. The key should be AMAZON_S3, but the underscore is being removed.

It happens because of this regexp, AMAZON_S3 doesn't match it. I guess the regexp should be changed in order to support names with digits.

[PSiemieniuk]

#1558