chore: bump version

Signed-off-by: Jintao Zhang <zhangjintao9020@gmail.com>
diff --git a/Makefile b/Makefile
index 52b7ffe..9a2ed4b 100644
--- a/Makefile
+++ b/Makefile
@@ -16,7 +16,7 @@
 #
 default: help
 
-VERSION ?= 1.4.1
+VERSION ?= 1.5.0-rc1
 RELEASE_SRC = apache-apisix-ingress-controller-${VERSION}-src
 REGISTRY ?="localhost:5000"
 IMAGE_TAG ?= dev