09_secrets_cm_pipeline fails to compile

[strangiato]

add_env_variable used in v1 no longer exists.

Attempted to switch to set_env_variable but it does not appear to accept the k8s secret as an option.

Full stack trace:

$ python pipelines/09_secrets_cm_pipeline.py          
Traceback (most recent call last):
  File "/Users/my-user/code/rhai/kubeflow-pipelines-examples/pipelines/09_secrets_cm_pipeline.py", line 27, in <module>
    @kfp.dsl.pipeline(
     ^^^^^^^^^^^^^^^^^
  File "/Users/my-user/code/rhai/kubeflow-pipelines-examples/.venv/lib/python3.11/site-packages/kfp/dsl/pipeline_context.py", line 65, in pipeline
    return component_factory.create_graph_component_from_func(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/my-user/code/rhai/kubeflow-pipelines-examples/.venv/lib/python3.11/site-packages/kfp/dsl/component_factory.py", line 673, in create_graph_component_from_func
    return graph_component.GraphComponent(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/my-user/code/rhai/kubeflow-pipelines-examples/.venv/lib/python3.11/site-packages/kfp/dsl/graph_component.py", line 68, in __init__
    pipeline_spec, platform_spec = builder.create_pipeline_spec(
                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/my-user/code/rhai/kubeflow-pipelines-examples/.venv/lib/python3.11/site-packages/kfp/compiler/pipeline_spec_builder.py", line 1919, in create_pipeline_spec
    build_spec_by_group(
  File "/Users/my-user/code/rhai/kubeflow-pipelines-examples/.venv/lib/python3.11/site-packages/kfp/compiler/pipeline_spec_builder.py", line 1292, in build_spec_by_group
    subgroup_container_spec = build_container_spec_for_task(
                              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/my-user/code/rhai/kubeflow-pipelines-examples/.venv/lib/python3.11/site-packages/kfp/compiler/pipeline_spec_builder.py", line 612, in build_container_spec_for_task
    env=[
        ^
  File "/Users/my-user/code/rhai/kubeflow-pipelines-examples/.venv/lib/python3.11/site-packages/kfp/compiler/pipeline_spec_builder.py", line 614, in <listcomp>
    .EnvVar(name=name, value=value)
     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: bad argument type for built-in operation