create diff section for past sponsors

Author: purna135

welcome.md

@@ -225,21 +225,33 @@ NumFOCUS is our non-profit umbrella organization.
 
 PyMC Labs offers professional consulting services for PyMC.
 :::
-:::{grid-item-card} Mistplay
+
+::::
+:::::
+
+## Past Sponsors
+
+*Many thanks to all our former sponsors who supported PyMC development.*
+
+:::::{container} full-width
+::::{grid} 1 2 2 3
+:gutter: 2
+
+:::{grid-item-card} Mistplay (2022-2023)
 :link: https://www.mistplay.com/
 
 <img src="https://github.com/pymc-devs/brand/blob/main/sponsors/sponsor_logos/mistplay2_white.png?raw=true"/>
 
 Mistplay is the world's leading Loyalty Program for mobile gamers.
 :::
-:::{grid-item-card} ODSC
+:::{grid-item-card} ODSC (2022-2023)
 :link: https://odsc.com/california/?utm_source=pymc&utm_medium=referral
 
 <img src="https://github.com/pymc-devs/brand/blob/main/sponsors/sponsor_logos/odsc/odsc_blue.png?raw=true"/>
 
 The future of AI gathers here.
 :::
-:::{grid-item-card} Adia Lab
+:::{grid-item-card} Adia Lab (2023-2024)
 :link: https://www.adialab.ae/
 
 <img src="https://github.com/pymc-devs/brand/blob/main/sponsors/sponsor_logos/adia-lab/adia-lab-transparent.png?raw=true"/>