No-op gem for JRuby for now

[headius]

Remove all shipped files and require path on JRuby until we can add JRuby's extension to the gem.

Temporary workaround for #48

[headius]

Appears to work properly for me locally. We will try to get the real extension bits in here early in 2023.

[] date $ gem install date-3.3.0-java.gem 
Successfully installed date-3.3.0-java
Parsing documentation for date-3.3.0-java
Installing ri documentation for date-3.3.0-java
Done installing documentation for date after 0 seconds
1 gem installed
[] date $ jruby -e 'require "date"'
[] date $ jruby -e 'gem "date"; require "date"'

[hsbt]

We try this by date-3.3.1

[dentarg]

@hsbt can you create a GitHub release (https://github.com/ruby/date/releases) for 3.3.1 so it matches https://rubygems.org/gems/date/versions?

[hsbt]

done https://github.com/ruby/date/releases/tag/v3.3.1