ci: update DTM server UpdateBranchSync=1

- Set environment variable UPDATEBRANCHSYNC=1 (UpdateBranchSync=0 with bug, maybe~~)

Author: wooln

.github/workflows/build_and_it.yml

@@ -51,6 +51,7 @@ jobs:
           tar -xvf dtm_1.18.0_linux_amd64.tar.gz
           pwd
           mkdir /home/runner/work/client-csharp/client-csharp/logs
+          export UPDATEBRANCHSYNC=1
           nohup ./dtm > /home/runner/work/client-csharp/client-csharp/logs/dtm.log 2>&1 &
           sleep 5
           curl "127.0.0.1:36789/api/dtmsvr/newGid"