Update sponsors.md

Author: Hubertus Tummescheit

content/events/american2024/sponsors.md

@@ -1,8 +1,9 @@
 ## Our Sponsor
-
+| | |
 |:-|:-:|
 |Platinum |<img src="modelon.jpg" width=400> |
 
+| | | | | 
 |:-|:-:|:-:|:-:|:-:|
 |Gold |<img src="claytex.jpg" width=250>|<img src="3ds2.jpeg" width=250>|<img src="2020_11_04_MKTG_ESI_Logo_ColorTagline_rgb.png" width=250>|<img src="juliacomputing.jpg" width=250>|
 |Silver|<img src="maplesoft.jpg" width=250>| | |