fix: Added py.typed to MANIFEST.in

[jamesbraza]

Adds py.typed to package metadata

• Closes py.typed marker is missing #1351
• Closes Bundle py.typed files with package #1228

[conventional-commit-lint-gcf]

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[parthea]

Thanks for the fix, @jamesbraza !

As per https://mypy.readthedocs.io/en/latest/installed_packages.html#creating-pep-561-compatible-packages, we still need the changes to MANIFEST.in for the .tar.gz archive

The instructions above are enough to ensure that the built wheels contain the appropriate files.
However, to ensure inclusion inside the sdist (.tar.gz archive), you may also need to modify the inclusion rules in your MANIFEST.in:

[jamesbraza]

@parthea thanks for sharing that mypy docs link, nice find. It looks like @clundin25 added back in the py.typed to MANIFEST.in, so this PR should be good to go