I'm trying to install dependencies by running bundle install.

My Gemfile specifies Ruby version as follows:

source 'https://rubygems.org'

ruby '2.6.6'


gem 'cocoapods', '1.10.2'
...

However when I run bundle install I get the following output:

geoff:PayPalMobileSafariExtension git:(develop*) $ bundle install
Fetching <internal URL>
Fetching gem metadata from https://rubygems.org/........
Resolving dependencies...
Bundler found conflicting requirements for the Ruby version:
  In Gemfile:
    Ruby (~> 2.6.6.0)

    <some-internal-dependency> was resolved to 1.0.0, which depends on
      Ruby (= 2.6.6)

It's saying that I specified Ruby version 2.6.6.0 which is completely nonsensical, no such Ruby version exists and that's not even in the Gemfile. What is causing this?

For context I am using rbenv to manage my Ruby versions, it is currently set to 2.6.6.