updating to rails 6, but "activerecord-session_store (~> 2.0) was resolved to 2.0.0, which depends on actionpack (>= 5.2.4.1)"

I ran bundle update rails and got this. I'm stumped. If activerecord-session_store 2.0 depends on a version of actionpack between 5.2.4.1 and above, and if actionpack is a dependency of Rails 6, shouldn't this be ok?

Bundler could not find compatible versions for gem "actionpack":
 In Gemfile:
  activerecord-session_store (~> 2.0) was resolved to 2.0.0, which depends on
   actionpack (>= 5.2.4.1)

 rails (~> 6.0.3.6) was resolved to 6.0.3.6, which depends on
  actionpack (= 6.0.3.6)

 devise (~> 4.2) was resolved to 4.8.0, which depends on
  responders was resolved to 3.0.1, which depends on
   actionpack (>= 5.0)

My gemfile is:

source 'https://rubygems.org'
ruby '2.5.0'

gem 'rails', '~> 6.0.3.6'
gem 'pg', ' 0.18.3'
gem 'devise', '~> 4.2'
gem 'aws-sdk-s3', '~> 1.75', require: false
gem 'friendly_id', '~> 5.1'
gem 'pagy', '~> 3.7', '>= 3.7.2'
gem 'activerecord-session_store', '~> 2.0'
gem 'sprockets', '3.7.2'
gem 'aasm', '~> 5.0'
gem 'redis', '~> 4.1', '>= 4.1.3'
gem 'sidekiq', '~> 6.0', '>= 6.0.4'
gem 'local_time', '~> 2.1'
gem 'stripe', '~> 5.11'
gem 'stripe_event', '~> 2.3'
gem 'lockbox', '~> 0.4.8'
gem 'mailgunner', '~> 2.4'
gem 'rack-attack'
gem 'honeypot-captcha', '~> 1.0', '>= 1.0.1'
gem 'rack-timeout', '~> 0.6.0'
gem 'pry', '0.13.1'
gem 'image_processing', '~> 1.11'
gem 'shrine', '~> 3.3.0'
gem 'marcel', '~> 0.3.3'
gem 'webpacker', '~> 5.2', '>= 5.2.1'
gem 'json', '~> 2.3', '>= 2.3.1'

Hmm; if I try bundle install with your Gemfile I get

Bundler could not find compatible versions for gem "marcel":
  In Gemfile:
    marcel (~> 0.3.3)

    rails (~> 6.0.3.6) was resolved to 6.0.3.6, which depends on
      activestorage (= 6.0.3.6) was resolved to 6.0.3.6, which depends on
        marcel (~> 1.0.0)

So try updating the version of marcel in your Gemfile to "~> 1.0.0" and then bundle update rails marcel.