prependToPATH method
Prepends path
to the start of the PATH
in a persistent manner.
Note: this doesn't update current scripts
path.
Returns true if we successfully prepended the path.
In almost all shells you will need to restart
the terminal in order for the path change to take affect.
Implementation
@override
bool prependToPATH(String path) =>
throw UnsupportedError('Not supported in zsh');