Upgrades Yarn 2 to latest version, moves pm field to the top

.pmm.js

@@ -2,7 +2,7 @@ const https = require('https');
 const fs = require('fs');
 const path = require('path');
 
-const REQUESTED_VERSION = require('./package.json').engines.pm.split('@')[1];
+const REQUESTED_VERSION = require('./package.json').pm.split('@')[1];
 const BERRY_URL = `https://raw.githubusercontent.com/yarnpkg/berry/%40yarnpkg/cli/${REQUESTED_VERSION}/packages/yarnpkg-cli/bin/yarn.js`;
 const YARN_DIR = path.join(__dirname, '.yarn');
 const RELEASES_DIR = path.join(YARN_DIR, 'releases');

package.json

@@ -1,9 +1,7 @@
 {
   "name": "mochapack",
-  "version": "2.0.0",
-  "engines": {
-    "pm": "[email protected]"
-  },
+  "version": "2.0.1",
+  "pm": "[email protected]",
   "description": "mocha cli with webpack support",
   "bin": "./bin/mochapack",
   "main": "./lib/createMochapack.js",