[None][chore] Add release/1.2 branch into lockfile generation schedule (#10790)

Signed-off-by: Yiqing Yan <yiqingy@nvidia.com>

jenkins/TensorRT_LLM_PLC.groovy

@@ -142,6 +142,7 @@ pipeline {
     triggers {
         parameterizedCron('''
             H 2 * * * %branchName=main;repoUrlKey=tensorrt_llm_github
+            H 3 * * * %branchName=release/1.2;repoUrlKey=tensorrt_llm_github
         ''')
     }