Make mkinstpkg support HTTPS locations
When preparing a Linux installation package on SAV for Linux 9.12.3, attempting to specify an update URL in the form "https://server.example.com/sophos" results in the message "The update source address must be a website or an absolute directory path." Keeping the same URL but removing the S, i.e. "http://server.example.com/sophos" works as expected.
Please enhance the tool to allow HTTPS locations so authentication passwords aren't sent in the clear.
