docs: show most recent logo
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- <a href="https://cee-studio.github.io/orca"><img src="https://raw.githubusercontent.com/cee-studio/orca-docs/1f3aee92c6d29ba8a51651cebc524c037ce9ae7d/docs/source/images/logo.svg" width="546" alt="orca" style="background-color:red;" /></a>
+ <a href="https://cee-studio.github.io/orca"><img src="https://raw.githubusercontent.com/cee-studio/orca-docs/master/docs/source/images/logo.svg" width="546" alt="orca" style="background-color:red;" /></a>
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