Fix deprecation

[deivid-rodriguez]

Summary

Trying to fix a deprecation message coming from the database_cleaner gem.

Fixes #459.

Details

My changes consist of:

• For the usage inside "lib", make sure to use the proper API according to its availabilty. That means using `DatabaseCleaner.cleaners if available.

• For the usages inside our own features, bump the database_cleaner in use to a high enough version, and switch to DatabaseCleaner.cleaners unconditionally.

Motivation and Context

Remove deprecation messages from test suites.

How Has This Been Tested?

Not yet, I'll start with CI, then test it on my project.

Types of changes

• Bug fix (non-breaking change which fixes an issue).
• New feature (non-breaking change which adds functionality).
• Breaking change (fix or feature that would cause existing functionality to not work as expected).

Checklist:

• I've added tests for my code.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[janko]

Thank you for working on this, I would appreciate not seeing this deprecation warning too 👍

[deivid-rodriguez]

No problem!

CI is failing due to an issue in the activerecord adapter of database_cleaner which I'm trying to fix here: DatabaseCleaner/database_cleaner-active_record#43.

[deivid-rodriguez]

Just tried in my library and it works 👍. Setting this as ready.

[olleolleolle]

This PR avoids a warning output by a supporting library. Looks good to me!

[deivid-rodriguez]

Great, thanks @olleolleolle!