fix(cookie extension): correction regex to match 'mi' (#2516)

src/extensions/cookie/bootstrap-table-cookie.js

@@ -136,7 +136,7 @@
 
     var calculateExpiration = function(cookieExpire) {
         var time = cookieExpire.replace(/[0-9]*/, ''); //s,mi,h,d,m,y
-        cookieExpire = cookieExpire.replace(/[A-Za-z]/, ''); //number
+        cookieExpire = cookieExpire.replace(/[A-Za-z]{1,2}}/, ''); //number
 
         switch (time.toLowerCase()) {
             case 's':