Add task that prints the date

and use the mock resource instead of busybox. avoids downloading an
entire image!

Signed-off-by: Taylor Silva <tsilva@pivotal.io>

tasks/hello-world.yml

@@ -1,8 +1,8 @@
 platform: linux
 
 image_resource:
-  type: registry-image
-  source: { repository: busybox }
+  type: mock
+  source: { mirror_self: true }
 
 run:
   path: echo

tasks/print-date.yml

@@ -0,0 +1,9 @@
+platform: linux
+
+image_resource:
+  type: mock
+  source: { mirror_self: true }
+
+run:
+  path: date
+  args: ["+%Y-%m-%d"]