Update .lycheeignore

Author: mre

.lycheeignore

@@ -1,7 +1,8 @@
 # Bot detection issue
-https://www.mathworks.com
+mathworks.com
 # Forbidden
 https://www.freepik.com/
-# Timeouts
+# (Occasional) Timeouts
 https://npo-echelon.ru/en/solutions/appchecker.php
-https://www.qualys.com/apps/container-security
+https://www.qualys.com/apps/container-security
+https://dickgrune.com/Programs/similarity_tester/