Update installation.rst

Default folder is now "public" and not "web"

Author: louvelmathieu

frontend/encore/installation.rst

@@ -57,7 +57,7 @@ is the main config file for both Webpack and Webpack Encore:
 
     Encore
         // directory where compiled assets will be stored
-        .setOutputPath('web/build/')
+        .setOutputPath('public/build/')
         // public path used by the web server to access the output path
         .setPublicPath('/build')
         // only needed for CDN's or sub-directory deploy