Change logo image URL in README

[Gerkiz]

Updated logo image source in README.

All Submissions:

• Have you checked to ensure there aren't other open Pull Requests for the same update/change?

Tested Changes:

1. Have you lint your code (luacheck .) locally prior to submission?

Changes to Core Features:

• Have you added an explanation of what your changes do and why you'd like us to include them?
• Have you successfully ran tests with your changes locally?

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