feat: add ruby2_keywords for ruby 3 compatibility (#109)

[drstrangelooker]

To deal with keyword argument incompatibilities between Ruby 3 and earlier versions (see https://www.ruby-lang.org/en/news/2019/12/12/separation-of-positional-and-keyword-arguments-in-ruby-3-0/), we can use the ruby2_keywords gem to decorate some of the functions that currently use the def method(*args) pattern that breaks in 3.0

[github-actions]

Ruby-CI Tests

   24 files     24 suites   3m 36s ⏱️
   73 tests    73 ✅ 0 💤 0 ❌
1 644 runs  1 644 ✅ 0 💤 0 ❌

Results for commit 898940e.