Rename ~Prometheus to ~Monitoring

CONTRIBUTING.md

@@ -171,7 +171,7 @@ Assigning a team label makes sure issues get the attention of the appropriate
 people.
 The current team labels are ~Build, ~"CI/CD", ~Discussion, ~Documentation, ~Edge,
-~Geo, ~Gitaly, ~Platform, ~Prometheus, ~Release, and ~"UX".
+~Geo, ~Gitaly, ~Platform, ~Monitoring, ~Release, and ~"UX".
 The descriptions on the [labels page][labels-page] explain what falls under the
 responsibility of each team.