sip: bump MNCC version sent to sipcon to 6

Match commit Iaca9ed6611fc5ca8ca749bbbefc31f54bea5e925 in osmo-sip-connector.

Change-Id: I39d55432776926a385e1b85b21bcdea8180a8946
diff --git a/sip/SIP_Tests.default b/sip/SIP_Tests.default
index 9fcd387..faf87c8 100644
--- a/sip/SIP_Tests.default
+++ b/sip/SIP_Tests.default
@@ -25,7 +25,7 @@
 
 [MODULE_PARAMETERS]
 Osmocom_VTY_Functions.mp_prompt_prefix := "OsmoSIPcon";
-MNCC_Emulation.mp_mncc_version := 5;
+MNCC_Emulation.mp_mncc_version := 6;
 
 [MAIN_CONTROLLER]