Add proper param to demo urls (#2007)

Author: imartinez

README.md

@@ -39,7 +39,7 @@ client is provided to test the API, together with a set of useful tools such as
 download script, ingestion script, documents folder watch, etc.
 
 > 💡 If you are looking for an **enterprise-ready, fully private AI workspace**
-> check out [Zylon's website](https://zylon.ai)  or [request a demo](https://cal.com/zylon/demo).
+> check out [Zylon's website](https://zylon.ai)  or [request a demo](https://cal.com/zylon/demo?source=pgpt-readme).
 > Crafted by the team behind PrivateGPT, Zylon is a best-in-class AI collaborative
 > workspace that can be easily deployed on-premise (data center, bare metal...) or in your private cloud (AWS, GCP, Azure...).
 

fern/docs/pages/overview/welcome.mdx

@@ -3,7 +3,7 @@ build **private, context-aware AI applications**.
 
 <Callout intent = "tip">
 If you are looking for an **enterprise-ready, fully private AI workspace**
-check out [Zylon's website](https://zylon.ai)  or [request a demo](https://cal.com/zylon/demo).
+check out [Zylon's website](https://zylon.ai)  or [request a demo](https://cal.com/zylon/demo?source=pgpt-docs).
 Crafted by the team behind PrivateGPT, Zylon is a best-in-class AI collaborative
 workspace that can be easily deployed on-premise (data center, bare metal...) or in your private cloud (AWS, GCP, Azure...).
 </Callout>