Ahoj Ondreji, I noticed the error message when using "-RuntimeVersion 7.1" parameter as you mentioned in the article (personally I do not need v7.1, but reporting in case you would like to have a look at it).
"New-AzAutomationModule : Cannot validate argument on parameter 'RuntimeVersion'. The argument "7.1" does not belong to the set "5.1,7.2" specified by the ValidateSet attribute. Supply an argument that is in the set and then try the command again."