Remove munin from README.md

Author: Firefishy

README.md

@@ -7,7 +7,7 @@ This repository is used by the [OpenStreetMap operations and administration team
 The OpenStreetMap [Chef](https://www.chef.io/) cookbooks used to automate the configuration of our servers is [available here](https://github.com/openstreetmap/chef).
 
 ### Server Monitoring
-The servers are monitored using [prometheus](https://prometheus.openstreetmap.org/), [munin](https://munin.openstreetmap.org/) and [statuscake](https://uptime.openstreetmap.org/).
+The servers are monitored using [prometheus](https://prometheus.openstreetmap.org/) and [statuscake](https://uptime.openstreetmap.org/).
 
 ### Current Hardware
 A [list of current OSMF hardware](https://hardware.openstreetmap.org/) is automatically built from Chef.