Depfu updates don't flow downsteam easily

[jagthedrummer]

When depfu makes an update it usually is just an update to Gemfile.lock and/or yarn.lock. When people update their app with the latest stuff from the starter repo those two files often contain lots of conflicts and it's often easier to checkout the version from your own app and then bundle install and/or yarn install. When you do that you lose updates that depfu has made.

I discovered this when trying to update the demo site.

I followed the step-wise upgrade instructions and then ran into this error when trying to run any rake task, some of which are run as part of the test suite:

rake aborted!
LoadError: cannot load such file -- prism/prism
<internal:/Users/jgreen/.asdf/installs/ruby/3.3.0/lib/ruby/3.3.0/rubygems/core_ext/kernel_require.rb>:37:in `require'
<internal:/Users/jgreen/.asdf/installs/ruby/3.3.0/lib/ruby/3.3.0/rubygems/core_ext/kernel_require.rb>:37:in `require'
<internal:/Users/jgreen/.asdf/installs/ruby/3.3.0/lib/ruby/3.3.0/rubygems/core_ext/kernel_require.rb>:37:in `require'
<internal:/Users/jgreen/.asdf/installs/ruby/3.3.0/lib/ruby/3.3.0/rubygems/core_ext/kernel_require.rb>:37:in `require'
<internal:/Users/jgreen/.asdf/installs/ruby/3.3.0/lib/ruby/3.3.0/rubygems/core_ext/kernel_require.rb>:37:in `require'
<internal:/Users/jgreen/.asdf/installs/ruby/3.3.0/lib/ruby/3.3.0/rubygems/core_ext/kernel_require.rb>:37:in `require'
/Users/jgreen/projects/bullet-train-co/bullet_train-demo-site/Rakefile:6:in `<top (required)>'
(See full trace by running task with --trace)

That led me to this issue: rails/rails#50709 (Hi, @gazayas!)

Which led me here: Shopify/bootsnap#463

And I finally realized that the starter repo is on version 1.17.1 of bootsnap but the demo site was on 1.16.0 due to the previously mentioned method of sorting out conflicts in the lock file.

I kinda think that we should explicitly pin every one of our dependencies in Gemfile so that it's obvious when things should flow downstream.