fix: Overthewire duplicate issue

Fixes https://github.com/trimstray/the-book-of-secret-knowledge/issues/134

README.md

@@ -1363,7 +1363,6 @@ AWS deployment tool.<br>
 &nbsp;&nbsp;:small_orange_diamond: <a href="https://crackmes.one/"><b>Crackmes</b></a> - download crackmes to help improve your reverse engineering skills.<br>
 &nbsp;&nbsp;:small_orange_diamond: <a href="https://domgo.at/cxss/intro"><b>DomGoat</b></a> - DOM XSS security learning and practicing platform.<br>
 &nbsp;&nbsp;:small_orange_diamond: <a href="https://chall.stypr.com"><b>Stereotyped Challenges</b></a> - upgrade your web hacking techniques today!<br>
-&nbsp;&nbsp;:small_orange_diamond: <a href="http://overthewire.org/wargames/"><b>OverTheWire</b></a> - can help you to learn and practice security concepts in the form of fun-filled games.<br>
 &nbsp;&nbsp;:small_orange_diamond: <a href="https://www.vulnhub.com/"><b>Vulnhub</b></a> - allows anyone to gain practical 'hands-on' experience in digital security.<br>
 &nbsp;&nbsp;:small_orange_diamond: <a href="https://w3challs.com/"><b>W3Challs</b></a> - is a penetration testing training platform, which offers various computer challenges.<br>
 &nbsp;&nbsp;:small_orange_diamond: <a href="https://ringzer0ctf.com/challenges"><b>RingZer0 CTF</b></a> - offers you tons of challenges designed to test and improve your hacking skills.<br>