feature: Improve Transform type

[karlismelderis-mckinsey]

Description

Please use unknown instead of any in Transform function params
It saved us from a lot of bug

this is an override that worked for us

declare module 'class-transformer' {
  export declare function Transform(
    transformFn: (params: {
      /**
       * there are edge cases where value is undefined hence it's better to always use `obj[key]`
       */
      value: never;
      key: string;
      obj: Record<string, unknown>;
      type: TransformationType;
      options: ClassTransformOptions;
    }) => unknown,
    options?: TransformOptions,
  ): PropertyDecorator;
}

Proposed solution