Conditionally disable apt-key usage (#235)
Disable apt-key usage when salt version is at least 3005, and the user
provides 'signed-by=' in their source, and we're on a newer version of
Debian or Ubuntu.
apt-key is deprecated, see the following for more context:
https://docs.saltproject.io/en/latest/ref/states/all/salt.states.pkgrepo.html#apt-key-deprecated
Signed-off-by: M. David Bennett <mdavidbennett@syntheticworks.com>