Update the usage of cp command depending on coreutils version

[f-alizada]

Recently there were changes in coreutils package which contains the cp command.
starting from 9.4-3 when using cp -n it results warning output: 'behavior of -n is non-portable and may change in future; use --update=none instead'

For more details:

• Download of .NET fails because of cp warning vscode-dotnet-runtime#1635
• https://debbugs.gnu.org/cgi/bugreport.cgi?bug=62572

In order to remove the warning the cp command usage should be updated depending on the version of the cp command installed (coreutils package)

[kasperk81]

cp -n isn't used in this repo?

[f-alizada]

@kasperk81 it is used here:

install-scripts/src/dotnet-install.sh

Line 964 in 33673ac

cp -R $override_switch "$root_path/$path" "$target"

[jessuppi]

Just fyi we had a discussion on our forum about this:

https://slickstack.io/forum/topic/cp-warning-behavior-of-n-is-non-portable-and-may-change-in-future

--update=none is also having issues, and it might not be a good idea to use it (yet).