Add an example in the README

I don't know if my output is normal. If it's not, I can open another issue.

/t/gaming-flightcheck ❯❯❯ ./print_checklist.py                                                                                                                           ✘ 130 
[OK] System file limit ok for Esync
[WARNING] CPU governor not set to performance

distro: Arch Linux (antergos)
XFCE
shell: Zsh
64 bit
CPU: i5-3320M
GPU: integrated intel [1]
mesa version 19.0.5-1
weather: cloudy
GNU sticker on laptop: in place

[1] I know that with such a GPU, even which Vulkan support, that might be useless. But

that's still a test can for gaming-flightcheck to be more robust
it's still worth it giving infos to intel 3rd gen CPU users so they won't spend too much time on software troubleshooting just to check if there hardware is still good enough for a given game
actually with D9VK that are many old games that should still run fin on such GPU and would benefit from using Vulkan & co

/t/gaming-flightcheck ❯❯❯ ./print_system_info.py

Distribution : Antergoslinux

GPU list :
    Intel 3rd Gen Core processor Graphics Controller (00:02.0)
        Available modules: i915
        Module in use: i915

OpenGL :
    Renderer: Mesa DRI Intel(R) Ivybridge Mobile 
    Vendor: Intel Open Source Technology Center
    OpenGL version: 3.0
    OpenGL vendor version: Mesa 19.0.4

Available CPU governors: performance/powersave
Current CPU governor: powersave

System file limit : 524288

Nvidia Page Attribute Table usage enabled : no

PRIME Sync : supported on 0 monitor(s), enabled on 0

Vulkan :
    libvulkan present :
        32-bit : no
        64-bit : yes
    Available ICDs :
    Extensions :

Packages checking is not supported for this distribution.

Askannz / gaming-flightcheck

Add an example in the README #7