chore: update sponsors (#2816)

Author: vue-bot

themes/vue/_config.yml

@@ -128,6 +128,9 @@ gold_sponsors:
   - url: 'https://linecorp.com'
     img: line_corporation.png
     name: LINE Corporation
+  - url: 'https://exmax.it/'
+    img: exmax.png
+    name: Exmax
 silver_sponsors:
   - url: 'https://roadster.com'
     img: roadster.png