build: Fix id in plugin metainfo files

data/misc/io.github.Hexchat.Plugin.metainfo.xml.in

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <component type="addon">
-  <id>io.github.Hexchat.Plugin.Perl</id>
+  <id>io.github.Hexchat.Plugin.@NAME@</id>
   <extends>io.github.Hexchat.desktop</extends>
   <name>@NAME@ Plugin</name>
   <summary>@SUMMARY@</summary>