Update sbt-mdoc to 2.2.4

Updates build (#140)

* Updates build

* Updates exercises version

Prepare repository for next `.github` release and SBT build improveme…

…nts (#122)

* Bumps up dependencies and sbt

* Reorders settings for making them simpler

* Updates command aliases

* Moves .docs to docs. Updates sbt module too

* Simplifies build

* Removes outdated smoketests module

* Removes unused imports. Reorder settings

* Updates sbt plugins

* Updates docs

Removes github fetch in ci-test command alias (#108)