fix readme for in-memory provider

Author: fabriziopandini

test/README.md

@@ -6,4 +6,4 @@ This package is not subject to deprecation notices or compatibility guarantees.
 
 - We iterate on the test framework quickly and frequently, and breaking changes are likely. External providers using this package should update to the latest API changes when updating Cluster API. Maintainers and contributors must give notice in release notes when a breaking change happens.
 
-- The docker provider, including its APIs, should only be used for development/testing purposes. Its API and code can change at any time without notice.
+- The docker and the in-memory providers, including their APIs, should only be used for development/testing purposes. APIs and code can change at any time without notice.

test/infrastructure/inmemory/README.md

@@ -1,3 +1,5 @@
 # Cluster API Provider In Memory (CAPIM)
 
-FIXME
+CAPIM is a implementation of an infrastructure provider for the Cluster API project using in memory, fake objects.
+
+**NOTE:** The In memory provider is **not** designed for production use and is intended for development environments only.