Use ghcr.io/appscode/gengo (#558)

Signed-off-by: Tamal Saha <tamal@appscode.com>

Makefile

@@ -21,7 +21,7 @@ BIN      := config-syncer
 COMPRESS ?= no
 
 CRD_OPTIONS          ?= "crd:allowDangerousTypes=true"
-CODE_GENERATOR_IMAGE ?= appscode/gengo:release-1.21
+CODE_GENERATOR_IMAGE ?= ghcr.io/appscode/gengo:release-1.25
 API_GROUPS           ?= kubed:v1alpha1
 
 # Where to push the docker image.