I found that the version of the mod on GitHub has been updated to 0.1.0, but it hasn't been updated here. Is there any way we can use the latest mod?

The version on the Github is not finished yet. There is at least one bug: it is possible to link belts of different tiers - by upgrading only one side of a linked pair.

Are you need to update only inlet or only outlet for the cheet? If both then it's not a cheat.

You do need to upgrade both sides to get the speed boost, otherwise the items decompress, so I guess it's not a cheat/cheese, but it is kind of annoying me. It might confuse players that don't know this if they assume it works like underground belts, and don't notice the other side is not upgraded.