chore: fix docs strict errros

docs/index.md

 [![moodle-plugin][moodle-plugin-badge-latest-tag]][moodle-plugin-repo] 
 [![backend][backend-badge-latest-tag]][backend-repo] 
-[![License GPLv3][badge-gplv3]][gplv3]
+![License GPLv3][badge-gplv3] 
 [![Conventional Commits][badge-conventional-commits]][convcomm] 
 
 # Dockerized Testing Toolkit (DTT)
@@ -26,7 +26,6 @@ and how to make assignments and submissions are found in this documentation.
 
 
 [convcomm]: https://conventionalcommits.org
-[gplv3]: unified-ticketing/license-softlink.md
 
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