Fix install example in readme

Closes #7051

Author: marijnh

README.md

@@ -1,7 +1,6 @@
 # CodeMirror
 
 [![Build Status](https://github.com/codemirror/codemirror5/workflows/main/badge.svg)](https://github.com/codemirror/codemirror5/actions)
-[![NPM version](https://img.shields.io/npm/v/codemirror.svg)](https://www.npmjs.org/package/codemirror)
 
 CodeMirror is a versatile text editor implemented in JavaScript for
 the browser. It is specialized for editing code, and comes with over
@@ -33,7 +32,7 @@ Either get the [zip file](https://codemirror.net/5/codemirror.zip) with
 the latest version, or make sure you have [Node](https://nodejs.org/)
 installed and run:
 
-    npm install codemirror
+    npm install codemirror@5
 
 **NOTE**: This is the source repository for the library, and not the
 distribution channel. Cloning it is not the recommended way to install