Fix/Upgrade typescript typing, loosen peer dependencies

* change typescript typing
* loosen peer dependencies
* add optional @type/react dependency

Author: Monar

package.json

@@ -1,6 +1,6 @@
 {
   "name": "react-immutable-pure-component",
-  "version": "1.2.2",
+  "version": "1.2.3",
   "description": "React PureComponent implementation embracing Immutable.js",
   "main": "lib/react-immutable-pure-component.js",
   "module": "lib/react-immutable-pure-component.es.js",
@@ -44,8 +44,11 @@
     "rollup-plugin-babel": "2.7.1"
   },
   "peerDependencies": {
-    "immutable": "^3 || ^4 || ^4.0.0-rc.0",
-    "react": "^15 || ^16",
-    "react-dom": "^15 || ^16"
+    "immutable": ">= 3",
+    "react": ">= 15",
+    "react-dom": ">= 15"
+  },
+  "optionalDependencies": {
+    "@types/react": "*"
   }
 }

types/react-immutable-pure-component.d.ts

@@ -1,8 +1,8 @@
-import * as React from 'react';
-declare module 'react-immutable-pure-component' {
-  export class ImmutablePureComponent<P,S> extends React.Component<P,S> {
+export as namespace ImmutablePureComponent;
+
+import { Component } from 'react';
+
+export class ImmutablePureComponent<P = {}, S = {}, SS = any> extends Component<P, S, SS> {
       updateOnProps: Array<keyof P>;
       updateOnStates: Array<keyof S>;
-      shouldComponentUpdate(nextProps: P, nextState?: S): boolean;
-  }
 }