pre-requirements: bump deprecated versions

Author: Pablo Panero

docs/install/index.md

@@ -8,7 +8,7 @@ command line tool for creating and updating your instance.
 Some system requirements are needed beforehand:
 
 - [Python](https://www.python.org/) (3.6.2 <= supported version < 3.7.0 only)
-- [nodejs](https://nodejs.org) (8.0.0+) (not needed to preview, only needed to develop)
+- [nodejs](https://nodejs.org) (10.0.0+) (not needed to preview, only needed to develop)
 - [Docker](https://docs.docker.com/) (1.13.0+)
 - [Docker-Compose](https://docs.docker.com/compose/) (1.17.0+)