drone: update drone to always pull in build step (#5)

- always pull the build image
- drop dind and use host docker socket
- drone fmt --save

.drone.yml

@@ -1,53 +1,49 @@
 ---
 kind: pipeline
 name: linux-amd64
+
 platform:
   os: linux
   arch: amd64
 
 steps:
 - name: build
+  pull: always
   image: rancher/hardened-build-base:v1.13.15b4
-  volumes:
-  - name: dockersock
-    path: /var/run
   commands:
-  - sleep 20
   - make DRONE_TAG=${DRONE_TAG}
+  volumes:
+  - name: docker
+    path: /var/run/docker.sock
 
 - name: publish
   image: rancher/hardened-build-base:v1.13.15b4
-  volumes:
-  - name: dockersock
-    path: /var/run
   commands:
   - docker login -u $DOCKER_USERNAME -p $DOCKER_PASSWORD
   - make DRONE_TAG=${DRONE_TAG} image-push image-manifest
   environment:
-    DOCKER_USERNAME:
-      from_secret: docker_username
     DOCKER_PASSWORD:
       from_secret: docker_password
+    DOCKER_USERNAME:
+      from_secret: docker_username
+  volumes:
+  - name: docker
+    path: /var/run/docker.sock
   when:
     event:
     - tag
 
 - name: scan
   image: rancher/hardened-build-base:v1.13.15b4
-  volumes:
-  - name: dockersock
-    path: /var/run
   commands:
   - make DRONE_TAG=${DRONE_TAG} image-scan
-
-services:
-- name: docker
-  image: docker:dind
-  privileged: true
   volumes:
-  - name: dockersock
-    path: /var/run
+  - name: docker
+    path: /var/run/docker.sock
 
 volumes:
-- name: dockersock
-  temp: {}
+- name: docker
+  host:
+    path: /var/run/docker.sock
+
+...