refactor: add "types" to package.json (#101)

TypeScript can't pick up the type definitions if they aren't in a "files" or "types" field

Co-authored-by: eyal0803 <eyal.3555@gmail.com>
Co-authored-by: Konstantin Kulinicenko <konstantin.kulinicenko@gmail.com>

Author: 3 people

package.json

@@ -3,6 +3,7 @@
   "version": "3.9.0",
   "description": "React component for entering and validating numbers, text or password.",
   "main": "dist/ReactCodeInput.js",
+  "types": "./src/ReactCodeInput.d.ts",
   "scripts": {
     "start": "npm run storybook",
     "build": "rm -r docs && mkdir docs && build-storybook -o docs && webpack && cd styles && sass style.scss style.css",
@@ -121,4 +122,4 @@
     "react": "^15.5.4 || ^16.2.0",
     "react-dom": "^15.5.4 || ^16.2.0"
   }
-}
+}