Why am I getting a concurrent-ruby gem conflict when using the rails new command?

I have created many rails projects to date without any problems. However when I tried to create a new project today using the command 'rails new pallet_tracker' I get the following error,

/home/billj/.rbenv/versions/2.5.3/lib/ruby/site_ruby/2.5.0/rubygems/specification.rb:2302:in `raise_if_conflicts': Unable to activate concurrent-ruby-ext-1.1.5, because concurrent-ruby-1.1.6 conflicts with concurrent-ruby (= 1.1.5) (Gem::ConflictError)

I get the same error when I enter the 'rails -v' command.

I am not sure how to resolve the conflict. There is no project so I can't change the gem file. Perhaps I have an outdated version of something but I don't know what that is. Any pointers will be gratefully received.

I continued with my google searches and found a suggestion that worked. I just ran 'gem update' and then 'rails new pallet_tracker' and everything worked.