chore: update sponsors

Author: Guillaume Chau

docs/.vuepress/style.styl

@@ -7,7 +7,7 @@
   margin 0 20px
 
 .gold-sponsor
-  max-width 300px !important
+  max-width 400px !important
 
 .silver-sponsor
   max-width 200px !important

docs/README.md

@@ -21,6 +21,14 @@ footer: LICENCE MIT - Created by Guillaume CHAU (@Akryum)
 
 ## Sponsors
 
+### Gold
+
+<p style="text-align: center;">
+  <a href="https://www.sumcumo.com/en/" target="_blank">
+    <img src="https://cdn.discordapp.com/attachments/258614093362102272/570728242399674380/logo-sumcumo.png" alt="sum.cumo logo" class="gold-sponsor">
+  </a>
+</p>
+
 ### Silver
 
 <p style="text-align: center;">