fix(dashboard): serialize image subtargets to prevent values.yaml write race

When make -j is used, image-console and image-token-proxy could run
concurrently and both do in-place edits to values.yaml, causing one
update to be silently lost. Add .NOTPARALLEL to force serial execution.

Signed-off-by: IvanHunters <xorokhotnikov@gmail.com>

packages/system/dashboard/Makefile

@@ -5,6 +5,7 @@ include ../../../hack/common-envs.mk
 include ../../../hack/package.mk
 
 .PHONY: image image-console image-token-proxy
+.NOTPARALLEL: image
 
 image: image-console image-token-proxy