Updated 'CORE_STABILITY' in Makefile to 'releases'.

Author: armandgrillet

Makefile

@@ -4,7 +4,7 @@ PKG_DIR=/go/src/$(PKG)
 IMAGE_NAME=dcos/dcos-cli
 VERSION?=$(shell git rev-parse HEAD)
 CORE_VERSION?=1.13-patch.0
-CORE_STABILITY?=testing
+CORE_STABILITY?=releases
 
 windows_EXE=.exe