iso.iso constructor is not equivalent to iso class constructor

[arthurgubaidullin]

🐛 Bug report

Current Behavior

composeIso does not accept an instance created via the iso.iso constructor.

Expected behavior

Both constructors must work with composeIso method.

Reproducible example

import { iso, Iso, Lens } from "monocle-ts";

type Input = { data: [string, string][] };

type Output = { data: { [id: string]: string } };

const data = Lens.fromProp<Input>()("data");

const iso1 = new Iso<Input["data"], Output["data"]>(
  () => {
    throw new Error("unimplemented");
  },
  () => {
    throw new Error("unimplemented");
  }
);

const iso2 = iso.iso<Input["data"], Output["data"]>(
  () => {
    throw new Error("unimplemented");
  },
  () => {
    throw new Error("unimplemented");
  }
);

data.composeIso(iso1); // this works!

data.composeIso(iso2); // type check error: Type 'Iso<[string, string][], { [id: string]: string; }>' is missing the following properties from type 'Iso<[string, string][], { [id: string]: string; }>': _tag, unwrap, to, wrap, and 19 more.

My environment

Software	Version(s)
monocle-ts	2.3.10
fp-ts	2.11.1
TypeScript	3.9.10