fix lint in formatEnv

Author: jozsefsallai

src/lib/formatEnv.js

@@ -1,5 +1,5 @@
 export default function (variable) {
-  if (!variable) return "";
+  if (!variable) return '';
 
   return variable.replace(
     /{{\s*(_.)?([a-zA-Z0-9_]+)\s*}}/g,