Replace askama with rinja

[GuillaumeGomez]

Recently, me and another askama maintainer forked the project into rinja. For more details about the why, I wrote a blog post here. But in short: rinja is ahead of askama now in a lot of areas so I think going forward, your project will benefit more from it.

If you're not interested about this switch, don't hesitate to close the PR.

If you want more information about rinja, don't hesitate to ask!

[sigaloid]

Thank you for the detailed blog post! The improvements seem compelling, so I'm happy to switch. You can ignore the failing test, but the fmt failing seems accurate - do you mind running cargo fmt to reorder the inputs in your branch, or would you prefer I do it in your branch?

[GuillaumeGomez]

Glad to hear it! I'll run cargo fmt. Didn't think about it. ^^'

[GuillaumeGomez]

Updated!

[sigaloid]

Awesome, thanks!