I did some work to update the mod to minecraft version 1.18. Everything seems to work fine, I wasn't exactly sure I did all the required changes correctly but everything that I use seems to work correctly. I can open a pull request but it doesn't appear that there is a 1.18 branch so I figured opening an issue and linking to my branch would be the best option.

https://github.com/MatthewManley/minihud/tree/fabric_1.18

For anyone seeing this and would like to test out my release, it can be found here, use at your own risk

There is here one temperary by masa already https://masa.dy.fi/tmp/minecraft/mods/misc_test_versions/minihud-fabric-1.18.0-0.19.0-dev.20211204.230657.jar

Awesome, didn't know that existed