Excluding retromat.org from link check

Author: spier

.lycheeignore

@@ -13,4 +13,5 @@ https://www.chathamhouse.org/about-us/chatham-house-rule
 https://www.linkedin.com/in
 # from source-code-inventory.md / no longer reachable but we want to keep the link in the pattern in case we find it again.
 https://github.com/trieshard/source-strategy-assessment/blob/master/framework.md
-https://dl.acm.org/doi/10.5555/3158161.3158175
+https://dl.acm.org/doi/10.5555/3158161.3158175
+https://retromat.org/en/