[readme] Update logo header

README.md

-<a href="https://github.com/nvm-sh/logos"><img alt="nvm project logo" src="https://raw.githubusercontent.com/nvm-sh/logos/HEAD/nvm-logo-color.svg" height="50" /></a>
+<a href="https://github.com/nvm-sh/logos">
+  <picture>
+    <source media="(prefers-color-scheme: dark)" srcset="https://raw.githubusercontent.com/nvm-sh/logos/HEAD/nvm-logo-white.svg" />
+    <img src="https://raw.githubusercontent.com/nvm-sh/logos/HEAD/nvm-logo-color.svg" height="50" alt="nvm project logo" />
+  </picture>
+</a>
+
 
 # Node Version Manager [![Build Status](https://app.travis-ci.com/nvm-sh/nvm.svg?branch=master)][3] [![nvm version](https://img.shields.io/badge/version-v0.39.3-yellow.svg)][4] [![CII Best Practices](https://bestpractices.coreinfrastructure.org/projects/684/badge)](https://bestpractices.coreinfrastructure.org/projects/684)