OTA-923: Promote ClusterVersionOperatorConfiguration to TechPreview

This missed 4.19 because of incomplete testing and docs, all of which is
remediated now, so this is ready for TechPreview.

Author: petr-muller

features/features.go

@@ -682,7 +682,7 @@ var (
 					contactPerson("dhurta").
 					productScope(ocpSpecific).
 					enhancementPR("https://github.com/openshift/enhancements/pull/1492").
-					enableIn(configv1.DevPreviewNoUpgrade).
+					enableIn(configv1.DevPreviewNoUpgrade, configv1.TechPreviewNoUpgrade).
 					mustRegister()
 
 	FeatureGateGCPCustomAPIEndpoints = newFeatureGate("GCPCustomAPIEndpoints").