Update default branch name for Redfish-Interop-Validator

Changes:
    - Update default master to main

Tested:
    - Tested from sandbox

Change-Id: I74f70559eea9c55498fe1ed6293c4bfaf35b6acd
Signed-off-by: George Keishing <gkeishin@in.ibm.com>
diff --git a/redfish/dmtf_tools/Redfish_Interop_Validator.robot b/redfish/dmtf_tools/Redfish_Interop_Validator.robot
index cb1c493..313fbda 100644
--- a/redfish/dmtf_tools/Redfish_Interop_Validator.robot
+++ b/redfish/dmtf_tools/Redfish_Interop_Validator.robot
@@ -14,7 +14,7 @@
 ...                --ip https://${OPENBMC_HOST}:${HTTPS_PORT} --authtype=Session -u ${OPENBMC_USERNAME}
 ...                -p ${OPENBMC_PASSWORD} --logdir ${EXECDIR}${/}logs${/} --debugging
 ...                ${EXECDIR}/data/openbmc_redfish_interop_profile.json
-${branch_name}     master
+${branch_name}     main
 
 *** Test Case ***