Modernize template weather

[gjohansson-ST]

Deprecation

The template weather entity have been updated:

• The forecast state attribute is deprecated and will be removed in Home Assistant Core 2024.3, users should instead call the service weather.get_forecast

Proposed change

Modernize SMHI weather:

• Add support for the weather.get_forecast service
• Add support for daily weather forecasts ( as it's a template I had to choose one )

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: Modernize weather template home-assistant.io#28532

Checklist

• The code change is tested and works locally.
• Local tests pass. Your PR cannot be merged unless tests pass
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• I have followed the development checklist
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• The code has been formatted using Black (black --fast homeassistant tests)
• Tests have been added to verify that the new code works.

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• Documentation added/updated for www.home-assistant.io

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• The manifest file has all fields filled out correctly.
  Updated and included derived files by running: python3 -m script.hassfest.
• New or updated dependencies have been added to requirements_all.txt.
  Updated by running python3 -m script.gen_requirements_all.
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[home-assistant]

Hey there @PhracturedBlue, @tetienne, @home-assistant/core, mind taking a look at this pull request as it has been labeled with an integration (template) you are listed as a code owner for? Thanks!

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[emontnemery]

Should we perhaps deprecate the forecast_template configuration parameter and replace with daily_forecast_template, hourly_forecast_template, twice_daily_forecast_template?

[home-assistant]

Please take a look at the requested changes, and use the Ready for review button when you are done, thanks 👍

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[emontnemery]

If the template rendered to None, it's fine to return None, but if we got a TemplateError, shouldn't we raise?
Also, we should check the result is a list and raise if it isn't.

[gjohansson-ST]

The template will take care of that and skip the validator and go directly to _update_forecast().
Didn't we say to always return an empty list even if there is something wrong with the forecast?

[emontnemery]

LGTM, thanks @gjohansson-ST 👍