Upgrade esm and use force option

This ensures user settings don't leak into our use of esm.

Author: novemberborn

package.json

@@ -33,7 +33,7 @@
 		"arrify": "^1.0.1",
 		"deep-strict-equal": "^0.2.0",
 		"enhance-visitors": "^1.0.0",
-		"esm": "^3.0.69",
+		"esm": "^3.0.71",
 		"espree": "^4.0.0",
 		"espurify": "^1.5.0",
 		"import-modules": "^1.1.0",

util.js

@@ -5,6 +5,7 @@ const isPlainObject = require('is-plain-object');
 const pkg = require('./package');
 const esmRequire = require('esm')(module, {
 	cjs: false,
+	force: true,
 	mode: 'all'
 });