Replace RequestStore with ActiveSupport::CurrentAttributes

[punkisdead]

Based on the work done here: #673 by @the-spectator

[punkisdead]

Since ActiveSupport::CurrentAttributes was introduced in Rails 5.2 Rails 5.2 Release I had to increase the minimum required version of activesupport and activerecord to 5.2.

I'm not entirely sure why the Fiber spec would pass on Rails 7.0 and not previous versions, but I'm not entirely sure we need that spec in this gem? ¯\_(ツ)_/¯

Even in current Rails, the default isolation level is set to :thread according to Configuring Rails

[danielmorrison]

👋
I think this a reasonable time to cut support for those old Rails versions. Up for cleaning up the build matrix? Otherwise I will in a bit.

[punkisdead]

I can take a look at it...

[danielmorrison]

I can't remember offhand why we added the fiber spec. Probably sanity check for… something. 🤷

[punkisdead]

I can't remember offhand why we added the fiber spec. Probably sanity check for… something. 🤷

It was added by @the-spectator in his PR.

[punkisdead]