fix checkin 3.0 (#321)

Author: aptend

.github/workflows/merge-trigger-tke.yaml

@@ -44,6 +44,7 @@ jobs:
         uses: actions/checkout@v6
         with:
           path: ./matrixone
+          ref: ${{ github.event.pull_request.base.ref }}
       - name: Login to TCR
         uses: docker/login-action@v3
         with:
@@ -126,6 +127,7 @@ jobs:
         uses: actions/checkout@v6
         with:
           path: ./matrixone
+          ref: ${{ github.event.pull_request.base.ref }}
       - name: Clean TKE ENV
         run: |
           if [ "$(kubectl -n mo-checkin-regression-${{ github.event.pull_request.number }} get mo | grep -c "mo-checkin-regression")" -ne 0 ];then