[v12] Use str helper to render markdown

[lakuapik]

As shown in this old tweet https://twitter.com/taylorotwell/status/1355188002818035713, taylor otwell introducing Str::markdown use within laravel. This PR change markdown renderer from Maillable to Str class helper.

The helper was introduced here laravel/framework#36171 and released here https://github.com/laravel/framework/releases/tag/v8.26.0.

[scrutinizer-notifier]

The inspection completed: No new issues

[lakuapik]

also, considering the rendered output using github flavored markdown, is it necessary to add the stylesheet too?
will use this https://github.com/sindresorhus/github-markdown-css to style the outputed markdown to make it more beautiful.

[tabacitu]

Totally - Str::markdown is much more intuitive, thank you @lakuapik . Unfortunately we'll only be able to merge this when we drop support for Laravel 6 and 7 (next major version) - because for those people this is a breaking change.

So we're totally going to merge this, but it's going to be a while.

Thank you @lakuapik !

[ziming]

oh wow my markdown column has changed so much since hehe

[tabacitu]

On second thought, unfortunately we can't merge this into 4.2 either... Backpack 4.2 will require Laravel 8.x, which includes versions BEFORE 8.25, which won't have Illuminate\Support\Str::markdown()

I'll move this to the next version of Backpack, when we will only support Laravel 9.x - only then can we merge this, unfortunately... Compatibility is a b*1ch 😅

[lakuapik]

@tabacitu i know your feelings, compatibility is s*cks 😆 😅

[tabacitu]

@lakuapik I have great news. I've just merged this PR into #4102 and that one into 4.2. Since in 4.2 we require Laravel 8 or higher, it isn't a big thing to require 8.26 or higher. So this is merged through #4102 - even if here it'll show up as closed.

Thank youuu 🙏