add platinum sponsor level

Author: strund3r

data/events/2025/goiania/main.yml

@@ -134,6 +134,8 @@ sponsors_accepted: "yes" # Whether you want "Become a XXX Sponsor!" link
 # unlimited sponsors, omit the max attribute or set it to 0. If you want to prevent all
 # sponsorship for a specific level, it is best to remove the level.
 sponsor_levels:
+  - id: platinum
+    label: Platinum
   - id: gold
     label: Gold
   #    max: 10