[readme] update CII badge URLs

Author: ljharb

README.md

@@ -6,7 +6,7 @@
 </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-v0.39.7-yellow.svg)][4] [![CII Best Practices](https://bestpractices.coreinfrastructure.org/projects/684/badge)](https://bestpractices.coreinfrastructure.org/projects/684)
+# 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-v0.39.7-yellow.svg)][4] [![CII Best Practices](https://bestpractices.dev/projects/684/badge)](https://bestpractices.dev/projects/684)
 
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