Write example DAG using Panglia dataset to support Astronomer's official docs

[tatiana]

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Context @jwitz has been writing the official Astronomer documentation at: https://github.com/astronomer/docs/pull/477/files

And he asked us to write a transform example using the Panglia dataset.

Acceptance criteria

• Create an example DAG which has transform and uses the Panglia dataset
• Share it with @jwitz in the Github thread