fix usage of petablint -y in docu

[jvanhoefer]

Which problem would you like to address? Please describe.

When looking at the docu, I saw that petablint is used via petablint -y <YamlFile>. Running this gives a deprecation warning for the -y argument. (And as I am not aware of the current prefered way of calling this, I open this issue) :)

Describe the solution you would like

Use the preferred way of calling this in the Notebook