add info about inventory app

InventoryAppExample/README.md

@@ -27,4 +27,10 @@ the estimated delivery date to their customer right away—the integration acts
 so quickly that the salesperson can see the estimated delivery date almost
 instantaneously after they close the opportunity. 
 
+A video demonstrating this app in action can be found on the
+[TrailheaDX](https://www.salesforce.com/trailheadx) website. After
+registering/logging in, go to [Product & Partner
+Demos](https://www.salesforce.com/trailheadx) and click `Integrations &
+Analytics` > `Platform APIs` to watch it.
+
 The proto file for the API can be found [here](https://github.com/developerforce/pub-sub-api-pilot/blob/main/pubsub_api.proto).

README.md

@@ -3,6 +3,8 @@
 Welcome to the Pub/Sub API Pilot! This repo contains the critical [proto
 file](https://github.com/developerforce/pub-sub-api-pilot/blob/main/pubsub_api.proto)
 that you will need to use the API. Refer to the pilot guide on how to use it.
+There is also a Python example app in this repo (`InventoryAppExample`
+directory); please read the README carefully.
 
 gRPC [officially supports 11 languages](https://grpc.io/docs/languages/), but
 there is unofficial community support in more. To encode and decode events, an