Fix typo in tfx.orchestration.config.PipelineConfig docstring
Fix typo in tfx.orchestration.config.PipelineConfig docstring

The current docstring is missing a `:` char, which prevents its proper parsing and formatting in the docs: https://www.tensorflow.org/tfx/api_docs/python/tfx/orchestration/config/pipeline_config/PipelineConfig
tensorflow/tfx,tensorflow/tfx