Updated WTB_REPO_TAG to 0.5 (#110)

The [Run 1x1 Wuestebach test case](https://github.com/HPSCTerrSys/eCLM/actions/runs/25153979206/job/73732652029?pr=110#step:13:17) step in our CI relied on https://github.com/HPSCTerrSys/eCLM_namelist-generator.git which has now been changed to https://github.com/HPSCTerrSys/ectk

Author: kvrigor

.github/workflows/build_and_run_eCLM.yml

@@ -71,7 +71,7 @@ jobs:
       INSTALL_DIR: ${{ github.workspace }}/install
       CMAKE_BUILD_PARALLEL_LEVEL: 4
       WTB_REPO_NAME: extpar_eclm_wuestebach_sp
-      WTB_REPO_TAG: 0.4
+      WTB_REPO_TAG: 0.5
 
     steps:
       - uses: actions/checkout@v4