Add metalmatze to list of maintainers (#1547)

Signed-off-by: Matthias Loibl <mail@matthiasloibl.com>
Signed-off-by: Giedrius Statkevičius <giedriuswork@gmail.com>

MAINTAINERS.md

@@ -7,10 +7,11 @@
 | Frederic Branczyk | fbranczyk@gmail.com | `@brancz` | [@brancz](https://github.com/brancz) |
 | Giedrius Statkevičius | giedriuswork@gmail.com | `@Giedrius Statkevičius` | [@GiedriusS](https://github.com/GiedriusS) |
 | Povilas Versockas | p.versockas@gmail.com | `@povilasv` | [@povilasv](https://github.com/povilasv) |
+| Matthias Loibl | mail@matthiasloibl.com | `@metalmatze` | [@metalmatze](https://github.com/metalmatze) |
 
 We are bunch of people from different companies with various interests and skills.
 We are from different parts of Europe: Germany, Lithuania, Poland and UK. 
-We have something in common though: We all share the love for OpenSource, Golang, Prometheus, :coffee: and Observability topics.
+We have something in common though: We all share the love for OpenSource, Go, Prometheus, :coffee: and Observability topics.
 
 As either Software Developers or SRE (or both!) we've chosen to maintain (mostly in our free time) Thanos, the de facto way to scale awesome [Prometheus](https://prometheus.io) project.
 
@@ -96,4 +97,5 @@ maintainer team.
 
 ## Initial authors
 
-Fabian Reinartz @fabxc and Bartłomiej Płotka @bwplotka
+Fabian Reinartz @fabxc and Bartłomiej Płotka @bwplotka
+