Make URI::ip() static by default

CHANGELOG.md

@@ -3,6 +3,7 @@
 
 1. [](#improved)
     * Updated jQuery from 2.2.0 to 2.2.3
+    * Set `Uri::ip()` to static by default so it can be used in form fields
 1. [](#bugfix)
     * Fixed "Invalid slug set in YAML frontmatter" when setting `Page::slug()` with empty string [#580](https://github.com/getgrav/grav-plugin-admin/issues/580)
     * Only `.gitignore` Grav's vendor folder

system/src/Grav/Common/Uri.php

@@ -687,7 +687,7 @@ class Uri
      *
      * @return string ip address
      */
-    public function ip()
+    public static function ip()
     {
         if (getenv('HTTP_CLIENT_IP'))
             $ipaddress = getenv('HTTP_CLIENT_IP');