Meltano

<https://github.com/meltano/sdk/pull/3705|#3705 refactor: Improve typing of `MetadataMapping.root`>
Pull request opened by <https://github.com/edgarrmondragon|edgarrmondragon>
*Summary by Sourcery*

Enhancements:
• Add type overloads and override for metadata item access to ensure `root` returns correctly typed stream metadata.
<https://github.com/meltano/sdk|meltano/sdk>

<https://github.com/meltano/sdk/pull/3705|#3705 refactor: Improve typing of `MetadataMapping.root`>
Pull request merged by <https://github.com/edgarrmondragon|edgarrmondragon>
<https://github.com/meltano/sdk|meltano/sdk>