Make createActionCreator simpler by removing `resolve` callback from executor

From TypeScript 3.0 we are able to infer function’s parameters with their names. So now we can remove resolve callback from executor in createActionCreator to make the API simpler.

Example:

// (name: string) => { type: "FETCH_TODOS"; }
createActionCreator("FETCH_TODOS");

// (name: string) => { type: "ADD_TODO"; payload: string; }
createActionCreator("ADD_TODO", (name: string) => ({ payload: name }));

There is one caveat point that has been encountered in #108 and that’s type property in return type of callable (2nd argument of proposed createActionCreator). One possible solution for the mentioned problem which I think is ideal is to set the type of type property to undefiend.

// Types of property 'type' are incompatible.
// Type 'string' is not assignable to type 'undefined'.ts(2345)
createActionCreator("ADD_TODO", (name: string) => ({ type: 'MISTAKE', payload: name }));

We can call the callable’s return type TypelessAction as it’s type should be undefined.

[the-dr-lazy]

Type '{ type: string; payload: string; }' is not assignable to type '"{ payload?: any, meta?: any }"'.

[the-dr-lazy]

I clicked “close issue” button by mistake. 😄