chore: fix sponsor link

Author: yyx990803

themes/vue/_config.yml

@@ -113,7 +113,7 @@ silver_sponsors:
   - url: 'https://www.thecasinodb.com'
     img: isolutions_uk_limited.png
     name: iSolutions UK Limited
-  - url: teamextension.io
+  - url: https://teamextension.io
     img: team_extension_north_america_inc.png
     name: Team Extension North America Inc
 bronze_sponsors: