grim/convey

Add a test for parsing the output of `aws ecr get-login`. Refs #161
# This test just verifies that the convely/clean task can take a single file or
# a list of files.
tasks:
clean-file:
type: convey/clean
files: i-do-not-exist
clean-files:
type: convey/clean
files:
- i-do-not-exist
- neither-do-i
plans:
default:
stages:
- tasks:
- clean-file
- clean-files