Update XML for release 10.0/bf (#1144)

Author: Rom1-B

plugin.xml

@@ -98,6 +98,11 @@ Il existe un [script de migration](https://github.com/pluginsGLPI/customfields/b
       <author>Olivier Moron</author>
    </authors>
    <versions>
+      <version>
+         <num>1.21.28</num>
+         <compatibility>~10.0.11</compatibility>
+         <download_url>https://github.com/pluginsGLPI/fields/releases/download/1.21.28/glpi-fields-1.21.28.tar.bz2</download_url>
+      </version>
       <version>
          <num>1.21.27</num>
          <compatibility>~10.0.11</compatibility>