mirage-monitoring: fix conflicts

Author: hannesm

packages/mirage-monitoring/mirage-monitoring.0.0.4/opam

@@ -21,7 +21,8 @@ depends: [
   "mirage-clock" {>= "4.0.0"}
 ]
 conflicts: [
-  "mirage-solo5" {< "8.0.2"}
+  "mirage-solo5" {< "0.9.2"}
+  "mirage-xen" {< "8.0.2"}
 ]
 build: [
   ["dune" "subst"] {dev}