Add gems which are not part of Ruby 3.4 to Gemfile to make knapsack_pro work on Ruby 3.4

[ArturT]

Add gems which are not part of Ruby 3.4 to Gemfile to make knapsack_pro work on Ruby 3.4

[ArturT]

After adjusting this rails app to make it work with Ruby 3.4-preview2, the CI builds on Ruby 3.3.1 fail with the error:

Downloading net-smtp-0.5.0 revealed dependencies not in the API or the lockfile
(net-protocol (>= 0)).
Running bundle update net-smtp should fix the problem.

But the rails app and tests with knapsack_pro work find locally.

I guess we need to use Ruby 3.4 on CI but there is no docker image available yet.
We have to wait until Ruby 3.4 is officially released.
If it does not help then the issue might be related to this one:

• net-protocol gets removed with ruby 3.3.3 ruby/net-pop#26 (comment)

Other than that we might want to update Rails 6 to 7 because now we have odd hacks in Gemfile:

# Fix for Ruby 3.1.x
# https://stackoverflow.com/a/70500221/905697
# https://github.com/mikel/mail/pull/1439
# This can be removed after upgrade to Rails 7.x
gem 'net-smtp', require: false
gem 'net-imap', require: false
gem 'net-pop', require: false