Flag modification of variables that are declared using const keyword as an error.

Author: RH Becker

packages/eslint-config-airbnb/rules/es6.js

@@ -32,7 +32,7 @@ module.exports = {
     // disallow modifying variables of class declarations
     'no-class-assign': 0,
     // disallow modifying variables that are declared using const
-    'no-const-assign': 0,
+    'no-const-assign': 2,
     // disallow to use this/super before super() calling in constructors.
     'no-this-before-super': 0,
     // require let or const instead of var