dev-ruby/prawn-icon: drop myself as a maintainer

Signed-off-by: Huang Rui <vowstar@gmail.com>

dev-ruby/prawn-icon/metadata.xml

@@ -1,10 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE pkgmetadata SYSTEM "https://www.gentoo.org/dtd/metadata.dtd">
 <pkgmetadata>
-	<maintainer type="person">
-		<email>vowstar@gmail.com</email>
-		<name>Huang Rui</name>
-	</maintainer>
+	<!-- maintainer-needed -->
 	<upstream>
 		<remote-id type="github">jessedoyle/prawn-icon</remote-id>
 	</upstream>