Update Dependencies & Drop Support for EOL Ruby versions

[thdaraujo]

Drop support for EOL Ruby versions.

The goal is to support ruby >= 2.7.

Tasks:

• [ ] Add deprecation warnings when running ruby < 2.7?
• [ ] #2527
• [ ] #2529

Fix Deprecations

• [ ] #2524
• [ ] #2525
• [ ] #2526

Fix Flaky tests

Let's keep track on the current flaky tests and start fixing them.

Tasks:

• [x] #2521

[thdaraujo]

~Should we first add a deprecation warning on the next release?~ nope!

[stefannibrasil]

Closing this one because all the tasks described here have been completed :tada: