Update gem dependencies and drop old versions of rails and ruby

[invalidusrname]

In an attempt to bring this gem up to date, I'm proposing we drop support for versions of ruby and rails that are no longer maintained:

Ruby changes

Ruby Versions Dropped:

• 2.7.5 - End of life, no longer receiving security updates
• 3.1.2 - Removed from CI test matrix

Ruby Versions Supported:

• 3.3.10 - Currently maintained stable version
• 4.0.1 - Latest stable version

Rails Versions Dropped:

• < 7.2 (currently the oldest version getting security updates)

Rails Versions Supported

• 7.2+

Other notable changes

• Updated CI matrix from ['3.1.2', '2.7.5'] to ["3.3.10", "4.0.1"]

• Removed bundler as a dev dependency

• Updated RuboCop configuration and linting

• Updated development dependencies (rspec-rails ~> 8.0, capybara > 3.40, sqlite3 > 2.9)

• Fixed Rails migration compatibility issues (removed timestamped_migrations check)

Dependencies Updated:

• friendly_id: unspecified → ~> 5.6
• nokogiri: conditional version logic → ~> 1.19
• Added MFA requirement for gem publishing

Deprecation Removals:

• Removed legacy counter_caching? method

[invalidusrname]

I did some initial testing with a new rails 8.1.2 app. Initializer and migrations seem ok using sqlite. I added logged a few impressions. If anyone else wants to give this a whirl, feel free to try it out and let me know if you find any problems. If not, I'll likely merge this into master in the upcoming week and put a full release out soon after