Update instrumentation readme to indicate pre-release status (#3263)

src/OpenTelemetry.Instrumentation.AspNetCore/README.md

@@ -6,10 +6,22 @@
 This is an [Instrumentation
 Library](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/glossary.md#instrumentation-library),
 which instruments [ASP.NET Core](https://docs.microsoft.com/aspnet/core) and
-collect telemetry about incoming web requests.
-This instrumentation also collects incoming gRPC requests using
+collect metrics and traces about incoming web requests. This instrumentation
+also collects traces from incoming gRPC requests using
 [Grpc.AspNetCore](https://www.nuget.org/packages/Grpc.AspNetCore).
 
+**Note: This component is based on the OpenTelemetry semantic conventions for
+[metrics](https://github.com/open-telemetry/opentelemetry-specification/tree/main/specification/metrics/semantic_conventions)
+and
+[traces](https://github.com/open-telemetry/opentelemetry-specification/tree/main/specification/trace/semantic_conventions).
+These conventions are
+[Experimental](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/document-status.md),
+and hence, this package is a [pre-release](../../VERSIONING.md#pre-releases).
+Until a [stable
+version](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/telemetry-stability.md)
+is released, there can be breaking changes. You can track the progress from
+[milestones](https://github.com/open-telemetry/opentelemetry-dotnet/milestone/23).**
+
 ## Steps to enable OpenTelemetry.Instrumentation.AspNetCore
 
 ### Step 1: Install Package