Quieten experimental warnings on example pipeline
Summary:
Previously, running dagit from the root of the Dagster git repository would give warnings such as:
/Users/max/dev/dagster/python_modules/dagster/dagster/core/definitions/output.py:195: ExperimentalWarning: "metadata" is an experimental argument to function "OutputDefinition.__init__". It may break in future versions, even between dot releases. To mute warnings for experimental functionality, invoke warnings.filterwarnings("ignore", category=dagster.ExperimentalWarning) or use one of the other methods described at https://docs.python.org/3/library/warnings.html#describing-warning-filters.Test Plan: Manual
Reviewers: dgibson, sandyryza, alangenfeld, prha
Reviewed By: alangenfeld
Differential Revision: https://dagster.phacility.com/D8145