Most interesting to us, 2.4.2 and 2.3.5 include the fix for
https://bugs.ruby-lang.org/issues/13632

`qu-redis` is need for qu adapter test.
However, since 8ecc5ab1, qu adapter test has not been executed,
it is unnecessary now.

I'm not sure this is the problem we're seeing on Travis (occasional
unexpected IOError exceptions), but it's worth a try.

This fork brings:

* A tiny refresh of the default theme.
* SEO tags to class files.
* The removal of HTML tags from search results.
* Some general template clean-up (HTML 5, removal of the jQuery
  effect library, etc.).
* A speed up of the generation time (by ~30 seconds).

thor 0.20.0 was released so we can test with the released version.

Follow up of https://github.com/rails/rails/commit/0b8441bd415c444b8d4afbfc93af79ec7677aa2c

No need to depend on my fork anymore, they've just release fix
officially.

```
% be rubocop -a --only Style/StringLiterals activestorage
Inspecting 74 files
........................................CCCCCCCCCC.C........CC.......C.C..

(snip)

74 files inspected, 31 offenses detected, 31 offenses corrected
```

"httparty" is only added in #30020 to write two tests to make PUT requests
against S3 and GCS.

The same requests can be made with net/http, removing a dependency from the Gemfile.

* Microsoft Azure storage support

* Add support for Microsoft Azure Storage

* Comply with the new headers implementation

This warning has been fixed in sass-rails. This change picks up the fix.

Thanks to rails/rails#29854! This does mean that we now depend on rails/rails master.

Bootsnap precomputes load path resolution and caches ruby ISeq
and YAML parsing/compilation, reducing application boot time by
approximately 50% on supported configurations.

Update google-cloud-storage dependency to 1.3
Refactor arguments to Google::Cloud::Storage::File#signed_url

Since we use new aws-sdk API, I've scoped aws-sdk version
so someone doesn't accidentaly installs wrong version during the
development.

This reverts commit 3420a145, reversing
changes made to afb66a5a.

The test using mathn was first introduced in f1d91790 to check that the
`distance_of_time_in_words` properly doesn't use the `Fixnum#/` method
by explicitly requiring this library as it redefines this method.

Given that `mathn` has been gemified in Ruby 2.5 and is deprecated since
version 2.2, we can certainly safely assume that people will most-likely
not require this library in their application.

However, to make sure that we don't regress, let's add a test similar to
the one before f1d91790.