Bump version to 2.0.0 and update minimum Redmine requirement to 6.0.0 in init.rb

Author: dkastl

init.rb

@@ -11,10 +11,10 @@
   author_url 'https://github.com/georepublic'
   url 'https://github.com/gtt-project/redmine_gtt_fiware'
   description 'Adds FIWARE integration capabilities for GTT projects'
-  version '1.1.0'
+  version '2.0.0'
 
   # Specify the minimum required Redmine version
-  requires_redmine :version_or_higher => '5.1.0'
+  requires_redmine :version_or_higher => '6.0.0'
 
   # Plugin settings with default values and partial view for settings
   settings(