from jsdeliver to jsDeliver

Hi all,

In the https://github.com/vuejs/vuejs.org/edit/master/src/v2/guide/installation.md file, at line 36, « Also available on [jsdelivr] » is mentionned. But accordingly with https://www.jsdelivr.com/, the correct typographie is `jsDelivr` so the correct sentence is 

« Also available on [jsDelivr] ».

We will use this typographie on french translation, we suggest you to do the same ;)