remove reference to old ephember logo

[ttroy50]

Proposed change

Remove the reference to the ephember logo from this repo as I have added icons to the brands repository. See home-assistant/brands#1290

Type of change

• Spelling, grammar or other readability improvements (current branch).
• Adjusted missing or incorrect information in the current documentation (current branch).
• Added documentation for a new integration I'm adding to Home Assistant (next branch).
  • [X ] I've opened up a PR to add logo's and icons in Brands repository.
• Added documentation for a new feature I'm adding to Home Assistant (next branch).
• Removed stale or deprecated documentation.

Additional information

• Link to parent pull request in the codebase:
• Link to parent pull request in the Brands repository: #239 add ephember icons brands#1290
• This PR fixes or closes issue: Update WeMo documentation. #239

Checklist

• [X ] This PR uses the correct branch, based on one of the following:
  • I made a change to the existing documentation and used the current branch.
  • I made a change that is related to an upcoming version of Home Assistant and used the next branch.
• [X ] The documentation follows the Home Assistant documentation standards.

[cogneato]

Thanks again, @ttroy50