Only include *.rb files in gem releases

[bruno-]

Description

Gem source code includes a couple markdown files in lib/async/. Those markdown files are included in the .gem release file.

Old/current files included in the gem release:

irb(main):002:0> Dir.glob('{lib}/**/*', File::FNM_DOTMATCH, base: __dir__)
=> 
["lib/.",
 "lib/async",
 "lib/async/barrier.md", # we want to ignore this one
 "lib/async/barrier.rb",
 "lib/async/clock.rb",
 "lib/async/condition.md", # we want to ignore this one
 "lib/async/condition.rb",
 "lib/async/node.rb",
 "lib/async/notification.rb",
 "lib/async/queue.rb",
 "lib/async/reactor.rb",
 "lib/async/scheduler.rb",
 "lib/async/semaphore.md", # we want to ignore this one
 "lib/async/semaphore.rb",
 "lib/async/task.rb",
 "lib/async/variable.rb",
 "lib/async/version.rb",
 "lib/async/wrapper.rb",
 "lib/async.rb",
 "lib/kernel",
 "lib/kernel/async.rb",
 "lib/kernel/sync.rb"]

New list of files that will be included in a gem:

irb(main):001:0> Dir.glob('{lib}/**/*.rb', File::FNM_DOTMATCH, base: __dir__)
=> 
["lib/async/barrier.rb",
 "lib/async/clock.rb",
 "lib/async/condition.rb",
 "lib/async/node.rb",
 "lib/async/notification.rb",
 "lib/async/queue.rb",
 "lib/async/reactor.rb",
 "lib/async/scheduler.rb",
 "lib/async/semaphore.rb",
 "lib/async/task.rb",
 "lib/async/variable.rb",
 "lib/async/version.rb",
 "lib/async/wrapper.rb",
 "lib/async.rb",
 "lib/kernel/async.rb",
 "lib/kernel/sync.rb"]

Types of Changes

• Maintenance.

Testing

I think this change is N/A for testing.