Correct my username

In the `contrib/` installation files my username was changed
incorrectly. The link is broken due to an issue with MODx.

Caused by phpbb/support-toolkit@1830e02349bee477e72f5f99c916dc0f4d745775
Merge remote branch 'Leximosi/fix-username' into stk/olympus
Update MODX files to the latest version and include Github link