Centos 7: Installation failed, reverting ./composer.json to its original content.
Attempting fresh install of Ratchet on Centos version 7.7 system, following the Install guide. Composer installed fine.

Problem is:

```
[root@localhost html]# php ./composer.phar require cboden/ratchet
Using version ^0.4.3 for cboden/ratchet
./composer.json has been updated
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - Installation request for cboden/ratchet ^0.4.3 -> satisfiable by cboden/ratchet[v0.4.3].
    - cboden/ratchet v0.4.3 requires react/socket ^1.0 || ^0.8 || ^0.7 || ^0.6 || ^0.5 -> satisfiable by react/socket[v0.5.0, v0.5.1, v0.6.0, v0.7.0, v0.7.1, v0.7.2, v0.8.0, v0.8.1, v0.8.10, v0.8.11, v0.8.12, v0.8.2, v0.8.3, v0.8.4, v0.8.5, v0.8.6, v0.8.7, v0.8.8, v0.8.9, v1.0.0, v1.1.0, v1.2.0, v1.2.1, v1.3.0, v1.4.0, v1.5.0, v1.6.0] but these conflict with your requirements or minimum-stability.

Installation failed, reverting ./composer.json to its original content.
```
-----
The file composer.json:
```
{
    "require": {
        "react/event-loop": "^0.4",
        "react/socket": "^0.4"
    },
    "minimum-stability": "dev",
    "prefer-stable": true
}
```
-----
Suggestions?
