Fix lint and remove shelljs (replaced with cross-spawn)

lib/resolver.js

@@ -1,7 +1,6 @@
 'use strict';
 const path = require('path');
 const fs = require('fs');
-const os = require('os');
 const _ = require('lodash');
 const globby = require('globby');
 const debug = require('debug')('yeoman:environment');
@@ -146,9 +145,9 @@ resolver.getNpmPaths = function () {
   // Yarn has a command to get the directory of global modules:
   // $ yarn global dir
   // > '.../global\n'
-  const testYarn = spawn.sync('yarn', ['global', 'dir'], { encoding: 'utf8' });
+  const testYarn = spawn.sync('yarn', ['global', 'dir'], {encoding: 'utf8'});
   if (!testYarn.error) {
-    paths.push(path.resolve(testYarn.stdout.strip(), '../link/');
+    paths.push(path.resolve(testYarn.stdout.trim(), '../link/'));
   }
 
   // Adds support for generator resolving when yeoman-generator has been linked

package.json

@@ -54,7 +54,6 @@
     "mocha": "^5.1.1",
     "nsp": "^3.2.1",
     "nyc": "^11.7.3",
-    "shelljs": "^0.8.2",
     "sinon": "^5.0.7",
     "sinon-test": "^2.1.3",
     "xo": "^0.18.1",

test/resolver.js

@@ -2,7 +2,7 @@
 const fs = require('fs');
 const path = require('path');
 const assert = require('assert');
-const shell = require('shelljs');
+const spawn = require('cross-spawn');
 const Environment = require('../lib/environment');
 
 const globalLookupTest = process.env.NODE_PATH ? it : xit;
@@ -17,9 +17,9 @@ describe('Environment Resolver', function () {
     before(function () {
       this.projectRoot = path.join(__dirname, 'fixtures/lookup-project');
       process.chdir(this.projectRoot);
-      shell.exec('npm install --no-package-lock', {silent: true});
-      shell.exec('npm install generator-jquery --no-package-lock', {silent: true});
-      shell.exec('npm install -g generator-dummytest generator-dummy --no-package-lock', {silent: true});
+      spawn.sync('npm', ['install', '--no-package-lock']);
+      spawn.sync('npm', ['install', 'generator-jquery', '--no-package-lock']);
+      spawn.sync('npm', ['install', '-g', 'generator-dummytest', 'generator-dummy', '--no-package-lock']);
 
       fs.symlinkSync(
 				path.resolve('../generator-extend'),
@@ -87,7 +87,7 @@ describe('Environment Resolver', function () {
       before(function () {
         this.projectSubRoot = path.join(this.projectRoot, 'subdir');
         process.chdir(this.projectSubRoot);
-        shell.exec('npm install --no-package-lock', {silent: true});
+        spawn.sync('npm', ['install', '--no-package-lock']);
       });
 
       beforeEach(function () {