Function clone

Clones the graph. Uses shallow clone, because it's all immutable

clone(graph): Readonly<{
    vertices: IMapImmutable<string, Readonly<{
        id: string;
        out: readonly Readonly<{
            id: string;
            weight?: number;
        }>[];
    }>>;
}>
Parameters
- graph: Readonly<{
      vertices: IMapImmutable<string, Readonly<{
          id: string;
          out: readonly Readonly<{
              id: string;
              weight?: number;
          }>[];
      }>>;
  }>
Returns Readonly<{
    vertices: IMapImmutable<string, Readonly<{
        id: string;
        out: readonly Readonly<{
            id: string;
            weight?: number;
        }>[];
    }>>;
}>