Add support for Composer 2

[SteelWagstaff]

This repo doesn't support installing with Composer 2:

candela-citation/composer.json

Line 23 in 083e08a

"composer/installers": "~1.0"

We'd like to update our bedrocks to using Composer 2, but can't when they include candela-citation as a dependency (and this is a required dependency for Achieving the Dream). Would you consider updating dependency to something like: "composer/installers": 1 - 2 or "composer/installers": "~1.0 || ~2.0"? I will open PR