Update to 5.0.0.beta1

1. rake update[v5.0.0-beta1]
2. Update version.rb and the README version

Author: glebm

README.md

@@ -20,7 +20,7 @@ Please see the appropriate guide for your environment of choice:
 Add `bootstrap` to your Gemfile:
 
 ```ruby
-gem 'bootstrap', '~> 5.0.0.alpha3'
+gem 'bootstrap', '~> 5.0.0.beta1'
 ```
 
 Ensure that `sprockets-rails` is at least v2.3.2.

assets/javascripts/bootstrap-sprockets.js

@@ -1,15 +1,15 @@
 //= require ./bootstrap/dom/data
 //= require ./bootstrap/dom/event-handler
+//= require ./bootstrap/alert
+//= require ./bootstrap/button
 //= require ./bootstrap/dom/manipulator
-//= require ./bootstrap/toast
 //= require ./bootstrap/dom/selector-engine
-//= require ./bootstrap/dropdown
-//= require ./bootstrap/alert
-//= require ./bootstrap/tooltip
+//= require ./bootstrap/carousel
 //= require ./bootstrap/collapse
+//= require ./bootstrap/dropdown
 //= require ./bootstrap/modal
-//= require ./bootstrap/tab
-//= require ./bootstrap/scrollspy
-//= require ./bootstrap/button
-//= require ./bootstrap/carousel
+//= require ./bootstrap/tooltip
 //= require ./bootstrap/popover
+//= require ./bootstrap/scrollspy
+//= require ./bootstrap/tab
+//= require ./bootstrap/toast