Use standalone crddiff tool

Signed-off-by: Fatih Türken <turkenf@gmail.com>

Makefile

@@ -62,6 +62,7 @@ UPTEST_LOCAL_CHANNEL = stable
 KUSTOMIZE_VERSION = v5.3.0
 YQ_VERSION = v4.40.5
 CROSSPLANE_VERSION = 1.14.6
+CRDDIFF_VERSION = v0.12.1
 
 -include build/makelib/k8s_tools.mk
 
@@ -216,15 +217,15 @@ e2e: local-deploy uptest
 
 # TODO: please move this to the common build submodule
 # once the use cases mature
-crddiff: $(UPTEST)
+crddiff:
 	@$(INFO) Checking breaking CRD schema changes
 	@for crd in $${MODIFIED_CRD_LIST}; do \
 		if ! git cat-file -e "$${GITHUB_BASE_REF}:$${crd}" 2>/dev/null; then \
 			echo "CRD $${crd} does not exist in the $${GITHUB_BASE_REF} branch. Skipping..." ; \
 			continue ; \
 		fi ; \
 		echo "Checking $${crd} for breaking API changes..." ; \
-		changes_detected=$$($(UPTEST) crddiff revision --enable-upjet-extensions <(git cat-file -p "$${GITHUB_BASE_REF}:$${crd}") "$${crd}" 2>&1) ; \
+		changes_detected=$$(go run github.com/upbound/uptest/cmd/crddiff@$(CRDDIFF_VERSION) revision --enable-upjet-extensions <(git cat-file -p "$${GITHUB_BASE_REF}:$${crd}") "$${crd}" 2>&1) ; \
 		if [[ $$? != 0 ]] ; then \
 			printf "\033[31m"; echo "Breaking change detected!"; printf "\033[0m" ; \
 			echo "$${changes_detected}" ; \