On a GitHub wiki page, if I type:
www.foobar.com
GitHub automatically assumes this is a URL and makes the text a hyperlink to http://www.foobar
You can use a zero-width space to prevent most auto-linkers from interpreting characters as a URL
Here's an example with a zero width space inserted between https and :
https
:
https://example.com/
To insert one, you can copy from the url above or this page
See also this thread on twitter