Makefile: Remove the unused verify-release target (#2759)

Signed-off-by: timflannagan <[email protected]>
Upstream-repository: operator-lifecycle-manager
Upstream-commit: d35ba4360bb955cd52500f206621e3f2c01bb519

Author: timflannagan

staging/operator-lifecycle-manager/Makefile

@@ -230,9 +230,6 @@ release: manifests
 	docker pull $(IMAGE_REPO):$(ver)
 	$(MAKE) target=upstream ver=$(ver) quickstart=true package
 
-verify-release: release
-	$(MAKE) diff
-
 package: olmref=$(shell docker inspect --format='{{index .RepoDigests 0}}' $(IMAGE_REPO):$(ver))
 package:
 ifndef target