Added pritunl icon

[AgentT30]

Added pritunl icon

@ua741 please review

[Eseltwift]

Hey 👋

Allow me to make a few suggestions for improvement.

First, the section on Pritunl should be added between PostNL and Privacy Guides to maintain the alphabetical order of the JSON file.

Additionally, the altNames field is only required if several names can refer to the same logo. Icon names are case insensitive.

Here is an example:

"title": "Battle.net",
"slug": "battlenet",
"altNames": [
  "Battle net",
  "Blizzard"
]

The main/official name is Battle.net, but the file name is different, so we're adding a slug field to point to the correct file. Finally, we can assume that some people will call their entry in a different way, so we're planning alternative names such as Battle net and Blizzard.

So there's no need to add an alternative name in your case, since it's identical (not case-sensitive) to the title field.