Remove unused runOutsideVue option from vue/sort-keys (#2655)

Author: FloEdelmann

Diff for: lib/rules/sort-keys.js

@@ -96,9 +96,6 @@ module.exports = {
           },
           natural: {
             type: 'boolean'
-          },
-          runOutsideVue: {
-            type: 'boolean'
           }
         },
         additionalProperties: false