Update README link in CONFIG_FORMAT.md

Link to README was referencing .schema file which does not exist.
Updated to use the .md file.

Change-Id: If79c08310e0c1115909d2e2081f3bc1721c1bad0
Signed-off-by: Chris Cain <cjcain@us.ibm.com>
diff --git a/CONFIG_FORMAT.md b/CONFIG_FORMAT.md
index f81d6b2..6dd15d7 100644
--- a/CONFIG_FORMAT.md
+++ b/CONFIG_FORMAT.md
@@ -111,7 +111,7 @@
 
 ## Configuration schema
 
-The config schema is documented in [README.md](schemas/README.schema)
+The config schema is documented in [README.md](schemas/README.md)
 
 ## Configuration Records - Baseboard Example