Make external links open in new tab/window

Since the logos we feature need to link to external websites they must open in a new tab/window. I do not see this option when editing a Logo Showcase.

Can you offer some coding to add to functions.php to force those links to open in a new tab/window?

I have seen some support tickets here offer direct edits to the core plugin files but I 100% do not want to do that as the change will be lost anytime the plugin is upgraded.

TIA!