Update README instructions for npm package.

Author: RubenVerborgh

README.md

@@ -3,9 +3,7 @@ A utility to facilitate command-line interaction with Solid servers.
 
 ## Installation
 ```
-git clone git@github.com:solid/solid-cli.git
-cd solid-cli
-npm install
+npm install -g @solid/cli
 ```
 
 ## Usage
@@ -15,5 +13,5 @@ USERNAME=ruben
 PASSWORD=ruben
 URL=https://drive.verborgh.org/inbox/
 
-curl "$URL" -H 'Authorization: Bearer '`bin/solid-bearer-token "$IDP" "$USERNAME" "$PASSWORD" "$URL"`
+curl "$URL" -H 'Authorization: Bearer '`solid-bearer-token "$IDP" "$USERNAME" "$PASSWORD" "$URL"`
 ```