"Install dependencies" needs additional command line options

TS and JS Grammar Extension version: 0.0.50 / latest

In README.md, it is documented that to install dependencies, npm install is all that is required. However, I've found that on my Windows 10 machine with Visual Studio 2017, I have to type npm install -g windows-build-tools in a PowerShell running with administrator privileges or oniguruma fails to be installed.

It appears that after I get it to build one time, I don't have to pass those extra arguments to npm.

I found my solution when someone else had a similar problem on superuser.com. I'm logging this here to help others having the same problem, and as a suggestion that the README.md be updated to include the extra arguments needed on Windows 10.

Mettez à jour les instructions d’installation des dépendances dans README.md pour le cas signalé sous Windows 10. Commencez par examiner les indications existantes concernant npm install et l’échec de oniguruma décrit dans l’issue ; le travail est terminé lorsque le README documente clairement la commande PowerShell supplémentaire à exécuter en tant qu’administrateur et dans quels cas elle est nécessaire.