Fix styleChecker errors

[PetrB09]

Needs to fix stylechecker errors in CI https://github.com/PetrB09/py2eo/runs/4645491194?check_suite_focus=true

[AndrewG0R]

The latest supported by stylecheker Scala version is 2.12 which is incompatible with current project Scala version. More info can be found on the official feature web page.

[dours]

@AndrewG0R even more info can be found here scalastyle/scalastyle#360 . The stylechecker for scala 2.13 is here https://scalastyle.beautiful-scala.com/

[dours]

many fixes are done in #83

[tdv42]

see #118