Fix v4_upgrade_guide URL

Author: pka

src/release_notes/QwcDockerUpgradeNotes.md

@@ -93,7 +93,7 @@ As a consequence, `/var/www` is not necessarily anymore the home directory of th
 
 Starting with v2022.01.08, the requirements of all services where updated to use Flask-JWT-Extended 4.3.1.
 
-Flask-JWT-4.x changes the JWT format (see [4.0.0 Breaking Changes](https://flask-jwt-extended.readthedocs.io/en/stable/v4_upgrade_guide/#encoded-jwt-changes-important)), which can result in QWC Services returning a `Missing claim: identity` error message.
+Flask-JWT-4.x changes the JWT format (see [4.0.0 Breaking Changes](https://flask-jwt-extended.readthedocs.io/en/stable/v4_upgrade_guide.html#encoded-jwt-changes-important)), which can result in QWC Services returning a `Missing claim: identity` error message.
 
 To avoid this:
 * Change your JWT secret key in `.env`.