docs(npm): update node requirements

Author: jsjoeio

docs/npm.md

@@ -2,18 +2,24 @@
 <!-- DON'T EDIT THIS SECTION, INSTEAD RE-RUN doctoc TO UPDATE -->
 # npm Install Requirements
 
-- [Ubuntu, Debian](#ubuntu-debian)
-- [Fedora, CentOS, RHEL](#fedora-centos-rhel)
-- [Alpine](#alpine)
-- [macOS](#macos)
-- [FreeBSD](#freebsd)
+- [npm Install Requirements](#npm-install-requirements)
+  - [Ubuntu, Debian](#ubuntu-debian)
+  - [Fedora, CentOS, RHEL](#fedora-centos-rhel)
+  - [Alpine](#alpine)
+  - [macOS](#macos)
+  - [FreeBSD](#freebsd)
 
 <!-- END doctoc generated TOC please keep comment here to allow auto update -->
 
-If you're installing the npm module you'll need certain dependencies to build
-the native modules used by VS Code.
+If you're installing the npm module you'll need certain dependencies to build the native modules used by VS Code.
 
-You also need at least node v12 installed. See [#1633](https://github.com/cdr/code-server/issues/1633).
+- Node.js: version `>= 12`, `<= 14`
+
+_Note: the Node.js version requirements are based on the VS Code Node.js requirements. See [here](https://github.com/microsoft/vscode/wiki/How-to-Contribute#prerequisites)._
+
+Related:
+
+- [#1633](https://github.com/cdr/code-server/issues/1633)
 
 ## Ubuntu, Debian