AutoDevOps test package fails on gems not supported by Heroku

Apparently there are a few gems that are not supported by Heroku, like sqlite3.

If herokuish detects these, it will fail the test and abort. Since we aren't deploying to Heroku, this behavior is undesirable.

 !     Failed to install gems via Bundler.
 !     Detected sqlite3 gem which is not supported on Heroku:
 !     https://devcenter.heroku.com/articles/sqlite3

Note that this gem does require the sqlite3 package to be installed locally, and it's not present on the herokuish image.