Round precipitation forecast to 1 decimal place

[priiduonu]

The OWM returns precipitation forecast values as they are submitted to their network. It can lead to values like 0.0025000000000004 mm which does not make sense and messes up the display card. This PR rounds the value to 1 decimal place.

Description:

Related issue (if applicable): fixes #

Pull request in home-assistant.github.io with documentation (if applicable): home-assistant/home-assistant.github.io#<home-assistant.github.io PR number goes here>

Example entry for configuration.yaml (if applicable):

Checklist:

• The code change is tested and works locally.
• Local tests pass with tox. Your PR cannot be merged unless tests pass

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

• Documentation added/updated in home-assistant.github.io

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

• New dependencies have been added to the REQUIREMENTS variable (example).
• New dependencies are only imported inside functions that use them (example).
• New or updated dependencies have been added to requirements_all.txt by running script/gen_requirements_all.py.
• New files were added to .coveragerc.

If the code does not interact with devices:

• Tests have been added to verify that the new code works.

[priiduonu]

Before:

After:

[fabaff]

Looks good to me 🐦

[Yevgenium]

Hello @priiduonu. Could you make the same PR for the OWM daily forecast?