Fix: switch from sync to async (#27)

Author: JPeer264

lib/helpers/cleanNodeModules.js

@@ -5,15 +5,15 @@ import path from 'path';
 const deleteNodeModules = () => {
   const cwd = process.cwd();
 
-  return fs.removeSync(path.join(cwd, 'node_modules'));
+  return fs.remove(path.join(cwd, 'node_modules'));
 };
 
 const installNodeModules = (hasYarn) => {
   if (hasYarn) {
-    return execa.shellSync('yarn');
+    return execa.shell('yarn');
   }
 
-  return execa.shellSync('npm i');
+  return execa.shell('npm i');
 };
 
 export {