Add new sponsor (#456)

Author: jemgillam

src/pages/sponsor.mdx

@@ -89,6 +89,7 @@ YOU!**
   <Sponsor name="Outbank" business avatar="/images/sponsors/outbank.png" />
   <Sponsor name="Constructive" business avatar="/images/sponsors/constructive.svg" />
   <Sponsor name="Carvajal Consultants, Inc. " />
+  <Sponsor name="Seaber" business avatar="/images/sponsors/Seaber.png" />
 </Sponsors>
 <Sponsors level="supporters">
   <Sponsor name="HR-ON" business />