base64 and csv will be bundled gem in Ruby 3.4

[JunichiIto]

Expected behavior

No warnings.

Actual behavior

I got the following warnings about base64 and csv when running geocoder tests in Ruby 3.3.0:

/Users/jnito/dev/oss/geocoder/lib/geocoder/lookups/google_premier.rb:2: warning: base64 was loaded from the standard library, but will no longer be part of the default gems since Ruby 3.4.0. Add base64 to your Gemfile or gemspec.
/Users/jnito/dev/oss/geocoder/lib/geocoder/lookups/maxmind.rb:3: warning: csv was loaded from the standard library, but will no longer be part of the default gems since Ruby 3.4.0. Add csv to your Gemfile or gemspec.

Please read the news below:
https://github.com/ruby/ruby/blob/v3_3_0/NEWS.md#stdlib-updates

RubyGems and Bundler warn if users do require the following gems without adding them to Gemfile or gemspec. This is because they will become the bundled gems in the future version of Ruby.

Steps to reproduce

bundle exec rake

Environment info

• Geocoder version: master
• Rails version: N/A
• Database (if applicable):
• Lookup (if applicable):