doc: Remove warning about 0.x being the stable version

1.x is stable now as per rubygems

Signed-off-by: Dorian Marié <[email protected]>

README.adoc

@@ -12,12 +12,8 @@
 {doc-link}[image:{doc-badge}[API Documentation]]
 ****
 
-NOTE: This is the 1.x *development* branch. For the 0.x *stable* branch, please
-  see: https://github.com/ixti/sidekiq-throttled/tree/0-x-stable[0-x-stable]
-
 Concurrency and threshold throttling for https://github.com/sidekiq/sidekiq[Sidekiq].
 
-
 == Installation
 
 Add this line to your application's Gemfile: