Fixed minimum repo window vertical size

ubl-settings-update-repo-add.glade

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<!-- Generated with glade 3.38.2 -->
+<!-- Generated with glade 3.40.0 -->
 <interface domain="ubl-settings-update">
   <requires lib="gtk+" version="3.24"/>
   <!-- interface-css-provider-path ubl-settings-update.css -->
@@ -15,6 +15,7 @@
   </object>
   <object class="GtkApplicationWindow" id="MainWindow">
     <property name="width-request">500</property>
+    <property name="height-request">300</property>
     <property name="can-focus">False</property>
     <property name="modal">True</property>
     <property name="icon-name">com.ublinux.ubl-settings-repomanager</property>