maint: Add link to sunset issue in README (#303)

## Which problem is this PR solving?

Add link to sunset issue in README.

Author: MikeGoldsmith

Diff for: OSSMETADATA

@@ -1 +1 @@
-osslifecycle=maintained
+osslifecycle=beingsunset

Diff for: README.md

@@ -1,8 +1,10 @@
 # Honeycomb Beeline for Python
 
-[![OSS Lifecycle](https://img.shields.io/osslifecycle/honeycombio/beeline-python?color=success)](https://github.com/honeycombio/home/blob/main/honeycomb-oss-lifecycle-and-practices.md)
+[![OSS Lifecycle](https://img.shields.io/osslifecycle/honeycombio/beeline-python?color=pink)](https://github.com/honeycombio/home/blob/main/honeycomb-oss-lifecycle-and-practices.md)
 [![Build Status](https://circleci.com/gh/honeycombio/beeline-python.svg?style=svg)](https://app.circleci.com/pipelines/github/honeycombio/beeline-python)
 
+⚠️**STATUS**: This project is being Sunset. See [this issue](https://github.com/honeycombio/beeline-python/issues/302) for more details.
+
 ⚠️**Note**: Beelines are Honeycomb's legacy instrumentation libraries. We embrace OpenTelemetry as the effective way to instrument applications. For any new observability efforts, we recommend [instrumenting with OpenTelemetry](https://docs.honeycomb.io/send-data/python/opentelemetry-sdk/).
 
 This package makes it easy to instrument your Python web application to send useful events to [Honeycomb](https://honeycomb.io), a service for debugging your software in production.