Use `pkg-dir`

It makes the code slightly simpler and it’s by me.

https://github.com/sindresorhus/pkg-dir

package.json

@@ -28,7 +28,7 @@
   },
   "homepage": "https://github.com/lukechilds/get-root-module",
   "dependencies": {
-    "find-root": "^1.1.0"
+    "pkg-dir": "^2.0.0"
   },
   "devDependencies": {
     "ava": "^0.19.1",

src/index.js

@@ -1,10 +1,9 @@
 'use strict';
 
-const findRoot = require('find-root');
+const pkgDir = require('pkg-dir');
 
 try {
-	const modulePath = findRoot(process.cwd());
-	module.exports = require(modulePath);
+	module.exports = require(pkgDir.sync());
 } catch (err) {
 	module.exports = undefined;
 }