Add types package for paho-mqtt

[cdce8p]

Proposed change

Stubs for paho-mqtt have recently been added to typeshed and released with the types-paho-mqtt package.
Add it to our test requirements to improve type checking.

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
• New feature (which adds functionality to an existing integration)
• Deprecation (breaking change to happen in the future)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue:
• Link to documentation pull request:

Checklist

• The code change is tested and works locally.
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• Tests have been added to verify that the new code works.

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  Updated and included derived files by running: python3 -m script.hassfest.
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  Updated by running python3 -m script.gen_requirements_all.
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[home-assistant]

Hey there @emontnemery, @jbouwh, mind taking a look at this pull request as it has been labeled with an integration (mqtt) you are listed as a code owner for? Thanks!

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[jbouwh]

Are these new type stubs issed via the existing imports?

[cdce8p]

Are these new type stubs issed via the existing imports?

Yes. Previously mypy would have just ignore / set to Any any imports from paho.mqtt. It will use the stubs now instead. https://mypy.readthedocs.io/en/stable/running_mypy.html#missing-library-stubs-or-py-typed-marker

[jbouwh]

Nice work,
Thanx @cdce8p !

[jbouwh]

Looks good!