doc: update a link of npm repository

PR-URL: #24969
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

doc/guides/maintaining-npm.md

@@ -17,7 +17,7 @@ changes can be reviewed and landed via the normal consensus seeking process.
 ## Step 1: Clone npm
 
 ```console
-$ git clone https://github.com/npm/npm.git
+$ git clone https://github.com/npm/cli.git npm
 $ cd npm
 ```