Update the example Dockerfile to run on k8s (#5412)

Signed-off-by: Jason Parraga <[email protected]>

docs/flyte_agents/developing_agents.md

@@ -140,14 +140,13 @@ You can test your agent in a {ref}`local Python environment <testing_agents_loca
 The following is a sample Dockerfile for building an image for a Flyte agent:
 
 ```Dockerfile
-FROM python:3.9-slim-buster
+FROM python:3.10-slim-bookworm
 
 MAINTAINER Flyte Team <[email protected]>
 LABEL org.opencontainers.image.source=https://github.com/flyteorg/flytekit
 
-WORKDIR /root
-ENV PYTHONPATH /root
-
+# additional dependencies for running in k8s
+RUN pip install prometheus-client grpcio-health-checking
 # flytekit will autoload the agent if package is installed.
 RUN pip install flytekitplugins-bigquery
 CMD pyflyte serve agent --port 8000
@@ -193,7 +192,7 @@ By running agents independently, you can thoroughly test and validate your agent
 controlled environment before deploying them to the production cluster.
 
 By default, all agent requests will be sent to the default agent service. However,
-you can route particular task requests to designated agent services by adjusting the FlytePropeller configuration. 
+you can route particular task requests to designated agent services by adjusting the FlytePropeller configuration.
 
 ```yaml
  plugins: