DOCSP-36552 -- Update Oracle supported dbs to include 11g

Author: jvincent-mongodb

source/getting-started/supported-databases.txt

@@ -39,7 +39,7 @@ Relational Migrator supports the following source databases:
      - Deployments 
 
    * - Oracle 
-     - 12c and higher
+     - 11g and higher
      - Self hosted, AWS RDS
 
    * - Microsoft SQL Server