make: remove kodata target

given that release generation is now done throguh `./hack/release.sh`
(either used directly or through `hack/setup.sh`), there's no need to
have that under Makefile anymore

Signed-off-by: Ciro S. Costa <ciroscosta@vmware.com>

Makefile

@@ -73,11 +73,3 @@ copyright:
 		-ignore site/static/\*\* \
 		-ignore site/themes/\*\* \
 		.
-
-kodata: cmd/cartographer/kodata
-
-cmd/cartographer/kodata: cmd/cartographer/kodata/ytt-linux-amd64
-
-cmd/cartographer/kodata/ytt-linux-amd64: Makefile
-	curl -sL https://github.com/vmware-tanzu/carvel-ytt/releases/download/v0.36.0/ytt-linux-amd64 -o cmd/cartographer/kodata/ytt-linux-amd64
-	chmod +x cmd/cartographer/kodata/ytt-linux-amd64