Added codeowners for the AzureCommunicationCommon (#1393)

* added codeowners for AzureCommunicationCommon

* removed acs-identity group

.github/CODEOWNERS

@@ -26,6 +26,9 @@
 # PRLabel: %Communication
 /sdk/communication/                                 @Azure/azure-sdk-communication-code-reviewers
 
+# PRLabel: %Communication - Common
+/sdk/communication/AzureCommunicationCommon/      @petrsvihlik @AikoBB @maximrytych-ms @ostoliarova-msft @mjafferi-msft
+
 # PRLabel: %Azure.Identity
 /sdk/identity/                                      @tjprescott @mpodwysocki