Update xknx to version 0.18.3

[farmio]

Proposed change

Update xknx from version 0.18.2 to version 0.18.3
XKNX/xknx@0.18.2...0.18.3

Changelog:

• Light: support for xyY-color (DPT 242.600)
• Updated / removed dependencies

Support for xy-color lights in from HA integration will be added in a separate PR.
This can be safely merged to current 2021.6 beta.

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)
• 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
• 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.
• Untested files have been added to .coveragerc.

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[probot-home-assistant]

Hey there @Julius2342, @marvin-w, mind taking a look at this pull request as its been labeled with an integration (knx) you are listed as a codeowner for? Thanks!
_{^{(message by CodeOwnersMention)}}

[emontnemery]

@farmio is the new xknx version needed for next beta or is this rather in preparation for xy-color?

[emontnemery]

LGTM

[farmio]

It's a preparation for XY-color.
It doesn't add any feature to HA directly.
Some unused dependencies were dropped.

So doesn't change anything besides saving some disk space.