Add deprecation to legacy forecast for Weather

[gjohansson-ST]

Proposed change

Adds deprecation notice to weather for legacy forecast attributes

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.
• Local tests pass. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the development checklist
• I have followed the perfect PR recommendations
• The code has been formatted using Black (black --fast homeassistant tests)
• Tests have been added to verify that the new code works.

If user exposed functionality or configuration variables are added/changed:

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

If the code communicates with devices, web services, or third-party tools:

• 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.
• For the updated dependencies - a link to the changelog, or at minimum a diff between library versions is added to the PR description.
• Untested files have been added to .coveragerc.

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• I have reviewed two other open pull requests in this repository.

[home-assistant]

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

Code owner commands

Code owners of weather can trigger bot actions by commenting:

• @home-assistant close Closes the pull request.
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[fellnerse]

LGTM

[emontnemery]

We could open an issue like we do here:

core/homeassistant/components/vacuum/__init__.py

Lines 385 to 398 in bf66dc7

	ir.async_create_issue(
	hass,
	DOMAIN,
	f"deprecated_vacuum_base_class_{self.platform.platform_name}",
	breaks_in_ha_version="2024.2.0",
	is_fixable=False,
	is_persistent=False,
	issue_domain=self.platform.platform_name,
	severity=ir.IssueSeverity.WARNING,
	translation_key="deprecated_vacuum_base_class",
	translation_placeholders={
	"platform": self.platform.platform_name,
	},
	)

[home-assistant]

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

Learn more about our pull request process.

[emontnemery]

Thanks, @gjohansson-ST 👍

Let's clean up the tests as discussed in discord in a follow-up