bump golang to 1.23 in clusterloader load-slos template

Author: bhavi-koduru

tests/tasks/generators/clusterloader/load-slos.yaml

@@ -61,7 +61,7 @@ spec:
       git checkout $(params.cl2-branch)
       git branch
   - name: prepare-loadtest
-    image: golang:1.22
+    image: golang:1.23
     workingDir: $(workspaces.source.path)
     script: |
       S3_RESULT_PATH=$(params.results-bucket)