Update README.md

Author: witold-swierzy

data-platform/core-converged-db/cross-model-database/README.md

@@ -1,7 +1,7 @@
-Cross Model Database
+# Cross Model Database
 This area focuses on discussing different data models supported by Oracle Converged Database
 
-License
+# License
 Copyright (c) 2023 Oracle and/or its affiliates.
 
 Licensed under the Universal Permissive License (UPL), Version 1.0.