BUG: Build error on Circle when it should be passing

[brianamarie]

I've gotten a build error on CircleCI, when it should be passing:

#!/bin/sh -eo pipefail
# Unable to parse YAML
# while constructing a mapping
#  in 'string', line 40, column 11:
#               name: run html proofer
#               ^
# found duplicate key command
#  in 'string', line 42, column 11:
#               command: bundle exec htmlproofer ... 
#               ^
# 
# -------
# Warning: This configuration was auto-generated to show you the message above.
# Don't rerun this job. Rerunning will have no effect.
false

I'm going to re-test, but wait for all of the builds, and see if I can figure more out. cc @ppremk @hollenberry @a-a-ron @beardofedu