docs: Update README.md logo

README.md

@@ -1,4 +1,4 @@
-<h1><img width=250px src="https://atsign.dev/assets/img/atPlatform_logo_gray.svg?sanitize=true"></h1>
+<h1><a href="https://atsign.com#gh-light-mode-only"><img width=250px src="https://atsign.com/wp-content/uploads/2022/05/atsign-logo-horizontal-color2022.svg#gh-light-mode-only" alt="The Atsign Foundation"></a><a href="https://atsign.com#gh-dark-mode-only"><img width=250px src="https://atsign.com/wp-content/uploads/2023/08/atsign-logo-horizontal-reverse2022-Color.svg#gh-dark-mode-only" alt="The Atsign Foundation"></a>
 
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