chore(ci): Update buildkit v0.5 (#594)

Signed-off-by: Brad Beam <brad.beam@talos-systems.com>

.drone.yml

@@ -44,8 +44,9 @@ steps:
   pull: always
   environment:
     BUILDKIT_HOST: tcp://buildkitd.ci.svc:1234
+    BINDIR: /usr/local/bin
   commands:
-    - make
+    - make drone
   volumes:
   - name: dockersock
     path: /var/run

Makefile

@@ -8,7 +8,7 @@ INITRAMFS_IMAGE ?= autonomy/initramfs-base:255b4fd
 
 # TODO(andrewrynhard): Move this logic to a shell script.
 VPATH = $(PATH)
-BUILDKIT_VERSION ?= v0.4.0
+BUILDKIT_VERSION ?= v0.5.0
 BUILDKIT_IMAGE ?= moby/buildkit:$(BUILDKIT_VERSION)
 BUILDKIT_HOST ?= tcp://0.0.0.0:1234
 BUILDKIT_CACHE ?= -v $(HOME)/.buildkit:/var/lib/buildkit
@@ -41,7 +41,14 @@ DOCKER_ARGS ?=
 # to allow tests to run containerd
 DOCKER_TEST_ARGS = --security-opt seccomp:unconfined --privileged -v /var/lib/containerd/
 
-all: ci rootfs initramfs kernel installer talos
+all: ci drone
+
+.PHONY: drone
+drone: rootfs initramfs kernel installer talos
+
+.PHONY: ci
+ci: builddeps buildkitd
+
 
 .PHONY: builddeps
 builddeps: gitmeta buildctl
@@ -52,7 +59,7 @@ gitmeta:
 buildctl: $(BINDIR)/buildctl
 
 $(BINDIR)/buildctl:
-	@mkdir $(BINDIR)
+	@mkdir -p $(BINDIR)
 	@wget -qO - $(BUILDCTL_ARCHIVE) | \
 		tar -zxf - -C $(BINDIR) --strip-components 1 bin/buildctl
 
@@ -78,9 +85,6 @@ ifneq ($(BUILDKIT_CONTAINER_RUNNING),$(BUILDKIT_CONTAINER_NAME))
 endif
 endif
 
-.PHONY: ci
-ci: builddeps buildkitd
-
 .PHONY: binaries
 binaries: buildkitd
 	@$(BINDIR)/buildctl --addr $(BUILDKIT_HOST) \