Add simonpasquier to the OWNERS file for prometheus installer

roles/openshift_prometheus/OWNERS

@@ -1,8 +1,10 @@
 # approval == this is a good idea /approve
 approvers:
   - pgier
+  - simonpasquier
   - zgalor
 # review == this code is good /lgtm
 reviewers:
   - pgier
+  - simonpasquier
   - zgalor