net-analyzer/munin-contrib: Add maintainer & unmask

Per https://github.com/gentoo/guru/pull/141#issuecomment-1963938331 and
https://github.com/gentoo/guru/pull/141#issuecomment-1974125492, I've
added myself as maintainer of munin-contrib and unmasked it.

Signed-off-by: Philippe Chaintreuil <gentoo_bugs_peep@parallaxshift.com>

net-analyzer/munin-contrib/metadata.xml

@@ -1,6 +1,10 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE pkgmetadata SYSTEM "https://www.gentoo.org/dtd/metadata.dtd">
 <pkgmetadata>
+  <maintainer type="person">
+    <email>gentoo_bugs_peep@parallaxshift.com</email>
+    <name>Philippe Chaintreuil</name>
+  </maintainer>
   <maintainer type="person">
     <email>lssndrbarbieri@gmail.com</email>
     <name>Alessandro Barbieri</name>

profiles/package.mask

@@ -491,7 +491,6 @@ media-gfx/fontdiff
 media-gfx/ufolint
 media-libs/lodepng
 media-libs/sjpeg
-net-analyzer/munin-contrib
 net-analyzer/munin-plugins-mendix
 net-libs/evpath
 net-libs/udt