old npm version in the documentation

[Tone866]

I was rtfm and noticed this:

# Verify that the correct nodejs and npm (automatically installed with nodejs)
# version has been installed
node --version # Should output v12.X or v10.X
npm --version # Should output 6.X

npm's actual release is 7.x, so I was wondering if the docu is simply a bit outdated or if there where issues with the new npm version, so the 6.x is recommended.

[Koenkk]

Added npm 7 here. (depends on the installed node version)

[Tone866]

Ok, thank you!