The package.json's "main" and "typings" fields get overwritten upon build

[shirakaba]

Given the following packages/expo-contacts-nativescript-plugin/package.json:

{
    "name": "@nativescript-community/expo-contacts-nativescript-plugin",
    "version": "1.0.0",
    "description": "Expo Contacts, adapted for NativeScript.",
    "main": "Contacts.js",
    "typings": "Contacts.d.ts",
    "nativescript": {
        "platforms": {
            "ios": "7.0.6",
            "android": "7.0.1"
        }
    },
    "repository": {
        "type": "git",
        "url": "https://github.com/nativescript-community/expo-nativescript.git"
    },
    "keywords": [
        "NativeScript",
        "JavaScript",
        "TypeScript",
        "iOS",
        "Android"
    ],
    "peerDependencies": {
        "@nativescript-community/expo-nativescript-adapter": "*",
        "@unimodules/core": "^5.5.1",
        "expo-contacts": "^8.6.0",
		"unimodules-file-system-interface": "^5.3.0",
        "unimodules-permissions-interface": "^5.3.0"
    },
    "devDependencies": {
        "@nativescript-community/expo-nativescript-adapter": "file:../dist/packages/expo-nativescript-adapter"
    },
    "author": {
        "name": "Jamie Birch",
        "email": "14055146+shirakaba@users.noreply.github.com"
    },
    "bugs": {
        "url": "https://github.com/nativescript-community/expo-nativescript"
    },
    "license": "MIT",
    "homepage": "https://github.com/nativescript-community/expo-nativescript/README.md",
    "readmeFilename": "README.md",
    "bootstrapper": "@nativescript/plugin-seed"
}

... Upon build, it the main and typings fields get rewritten thus when output to dist/packages/expo-contacts-nativescript-plugin/package.json:

    "main": "index.js",
    "typings": "index.d.ts",

Could it please be kept consistent with the source package.json?