fix(core): support querystring only url for isRelativeURL (#492)

Author: yangineer

lib/core/utilities.js

@@ -4,7 +4,7 @@ export const isSet = o => !isUnset(o)
 export const isSameURL = (a, b) => a.split('?')[0] === b.split('?')[0]
 
 export const isRelativeURL = u =>
-  u && u.length && /^\/[a-zA-Z0-9@\-%_~][/a-zA-Z0-9@\-%_~]*[?]?([^#]*)#?([^#]*)$/.test(u)
+  u && u.length && /^\/([a-zA-Z0-9@\-%_~][/a-zA-Z0-9@\-%_~]*)?([?][^#]*)?(#[^#]*)?$/.test(u)
 
 export const parseQuery = queryString => {
   const query = {}