Add a method/option to read from a string/JSON

[tommy-mitchell]

Based on the title/synopsis, I expected this to also be able to normalize a file in memory. I wanted to do this for np (for sindresorhus/np#88):

const getPackageJsonFromLastRelease = async pkgPath => {
	const pkg = await gitUtil.readFileFromLastRelease(pkgPath);
	return readPackage(pkg);
	//=> Promise<NormalizedPackageJson>
};

Should read-pkg support this? Since normalize-package-data is already a dependency, adding this capability saves a user adding two dependencies instead of one.

[tommy-mitchell]

Possible signature:

import type {PackageJson} from 'type-fest';

const parsePackage = (package: PackageJson | string) => NormalizedPackageJson;

[sindresorhus]

Possible signature:

👍