In brief, you simply add the below to your apt preferences, most commonly (in mint, ubuntu and debian) as a new file created in /etc/apt/preferences.d/, which I chose to call sublime-text.pref. This preferences choice is simply going to give higher priority to the official package origin of download.sublimetext.com than other repositories on the system, and is going to do so only for the sublime-text package (just to be safe).