Fix Docker COPY paths for goreleaser dockers_v2 platform layout

Makefile

@@ -46,6 +46,7 @@ package: package-k3k package-k3k-kubelet	## Package the k3k and k3k-kubelet Dock
 .PHONY: package-%
 package-%:
 	docker build -f package/Dockerfile.$* \
+		--build-arg BIN_DIR=bin \
 		-t $(REPO)/$*:$(VERSION) \
 		-t $(REPO)/$*:latest  \
 		-t $(REPO)/$*:dev .

package/Dockerfile.k3k

@@ -1,9 +1,15 @@
 FROM registry.suse.com/bci/bci-base:16.1
 
-ARG BIN_K3K=bin/k3k
-ARG BIN_K3KCLI=bin/k3kcli
+ARG TARGETPLATFORM
+# BIN_DIR is the directory containing the binaries within the build context.
+# GoReleaser (dockers_v2) stages binaries under a per-platform directory that
+# matches TARGETPLATFORM (e.g. linux/amd64), so that is the default. Other
+# callers (e.g. the Makefile) can override it, for example with BIN_DIR=bin.
+ARG BIN_DIR=${TARGETPLATFORM}
+ARG BIN_K3K=k3k
+ARG BIN_K3KCLI=k3kcli
 
-COPY ${BIN_K3K} /usr/bin/
-COPY ${BIN_K3KCLI} /usr/bin/
+COPY ${BIN_DIR}/${BIN_K3K} /usr/bin/
+COPY ${BIN_DIR}/${BIN_K3KCLI} /usr/bin/
 
 CMD ["k3k"]

package/Dockerfile.k3k-kubelet

@@ -1,8 +1,14 @@
 # TODO: swicth this to BCI-micro or scratch. Left as base right now so that debug can be done a bit easier
 FROM registry.suse.com/bci/bci-base:16.1
 
-ARG BIN_K3K_KUBELET=bin/k3k-kubelet
+ARG TARGETPLATFORM
+# BIN_DIR is the directory containing the binaries within the build context.
+# GoReleaser (dockers_v2) stages binaries under a per-platform directory that
+# matches TARGETPLATFORM (e.g. linux/amd64), so that is the default. Other
+# callers (e.g. the Makefile) can override it, for example with BIN_DIR=bin.
+ARG BIN_DIR=${TARGETPLATFORM}
+ARG BIN_K3K_KUBELET=k3k-kubelet
 
-COPY ${BIN_K3K_KUBELET} /usr/bin/
+COPY ${BIN_DIR}/${BIN_K3K_KUBELET} /usr/bin/
 
 ENTRYPOINT ["/usr/bin/k3k-kubelet"]