Use long curl options

doc/install/installation.md

@@ -168,7 +168,7 @@ are out of date, so we'll need to install through the following commands:
     curl --location https://deb.nodesource.com/setup_7.x | sudo bash -
     sudo apt-get install -y nodejs
-    curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
+    curl --silent --show-error https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add -
     echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list
     sudo apt-get update
     sudo apt-get install yarn