fix: Root directory lookup

Author: kaiwalyajoshi

Makefile

@@ -2,7 +2,7 @@ ifeq ($(origin TRIVY_VERSION), undefined)
 $(error Required env-var TRIVY_VERSION has not been set, please set TRIVY_VERSION to the version matching the NKP/DKP release. See README for details)	
 endif 
 
-ROOT_DIR := $(shell cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
+ROOT_DIR := $(shell git rev-parse --show-toplevel)
 TIMESTAMP ?= $(shell date -u +%Y%m%dT%H%M%SZ )
 
 REGISTRY ?= docker.io