Update oracle-database-regions.md

ADB available in Singapore

Author: taylorrees1

articles/oracle/oracle-db/oracle-database-regions.md

@@ -26,7 +26,7 @@ The list below mentions the Azure and corresponding OCI regions with the regiona
 | Australia East | Australia East (Sydney) | ✓         | ✓      |   Dual   |
 | Australia Southeast | Australia Southeast (Melbourne) | ✓         |      |   Dual   |
 | Japan East | Japan East (Tokyo) | ✓         |       |   Dual   |
-| Southeast Asia |Singapore (Singapore) | ✓         |       |   Dual   |
+| Southeast Asia |Singapore (Singapore) | ✓         | ✓       |   Dual   |
 
 
 ## Brazil