Update pack config

Signed-off-by: Natalie Arellano <[email protected]>

Author: Natalie Arellano

content/docs/extension-author-guide/create-extension/build-dockerfile.md

@@ -83,7 +83,7 @@ Successfully built image hello-extensions
 ### See the image fail to run
 
 ```
-docker run hello-extensions
+docker run --rm hello-extensions
 ```
 
 You should see:

content/docs/extension-author-guide/create-extension/run-dockerfile.md

@@ -111,7 +111,7 @@ Successfully built image hello-extensions
 
 <!-- test:exec -->
 ```bash
-docker run hello-extensions
+docker run --rm hello-extensions
 ```
 
 You should see something akin to:

content/docs/extension-author-guide/create-extension/setup-local-environment.md

@@ -54,13 +54,17 @@ pack version
 
 The version should be at least `0.28.0`
 
-### Enable experimental features in pack
+### Update pack configuration
 
 <!-- test:exec -->
 ```bash
 pack config experimental true
+pack config lifecycle-image --unset
 ```
 
+As base image extension with Dockerfiles is currently an experimental feature, we must enable it in `pack`.
+We unset any custom lifecycle image that may have been provided to ensure that the latest version is used.
+
 ### Clone the samples repo
 
 <!-- test:exec -->