[18.0-fr6] Update Makefile for 18.0-fr6

Author: ospk8s-branching-bot[bot]

Makefile

@@ -383,7 +383,7 @@ scale-down-placement-controller-csv:
 	fi
 
 CRD_SCHEMA_CHECKER_VERSION ?= release-4.16
-BRANCH ?= main
+BRANCH ?= 18.0-fr6
 .PHONY: force-bump
 force-bump: ## Force bump operator and lib-common dependencies
 	for dep in $$(cat go.mod | grep openstack-k8s-operators | grep -vE -- 'indirect|placement-operator|^replace' | awk '{print $$1}'); do \