Update affiliation of Bryan Boreham (cortexproject#4541)

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>

Author: bboreham

MAINTAINERS

@@ -1,5 +1,5 @@
 Alvin Lin, Amazon Web Services <alvinlin123@gmail.com> (@alvinlin123)
-Bryan Boreham <bjboreham@gmail.com> (@bboreham)
+Bryan Boreham, Grafana Labs <bjboreham@gmail.com> (@bboreham)
 Goutham Veeramachaneni, Grafana Labs <gouthamve@gmail.com> (@gouthamve)
 Jacob Lisi, Grafana Labs <jacob.t.lisi@gmail.com> (@jtlisi)
 Marco Pracucci, Grafana Labs <marco@pracucci.com> (@pracucci)