Update olm.maxOpenShiftVersion to 4.18

olm.maxOpenShiftVersion in STO should be 4.18 instead of 4.16

This wrongly set config is preventing STF users to easily perform
upgrades to the latest OCP supported version

Closes-Bug: OSPRH-18670

Author: vkmc

deploy/olm-catalog/service-telemetry-operator/metadata/properties.yaml

@@ -1,6 +1,6 @@
 properties:
   - type: olm.maxOpenShiftVersion
-    value: "4.16"
+    value: "4.18"
   - type: olm.constraint
     value:
       failureMessage: Require Smart Gateway for Service Telemetry Framework