chore: remove `ember-cli-htmlbars` from dependencies (#164)
chore: remove `ember-cli-htmlbars` from dependencies (#164)

Since this addon provides no templates, it doesn't have to ship the
`ember-cli-htmlbars` as a dependency. This prevents it from being added
to the dependencies of an installer of `ember-percy` if they are using
an older version.
percy/ember-percy,percy/ember-percy,percy/ember-percy