new icon: pug (original, plain)

[GCHQDeveloper926]

• PR does not match another non-stale PR currently opened
• PR name matches the format new icon: Icon name (versions separated by comma). More details here
• PR's base is the develop branch.
• Your icons are inside a folder as seen here
• SVG matches the standards laid out here
• A new object is added in the devicon.json file at the correct alphabetic position as seen here

**This PR closes #567 **

Link to prove your SVG is correct and up-to-date.

(https://github.com/pugjs/pug-logo/blob/master/SVG/pug-final-logo-_-colour-128.svg)

[GCHQDeveloper926]

First PR into here but hopefully have met all the required points.
Do I need to remove the title/formatting from original SVG that I've copied?

[canaleal]

Good work, the SVG is 128x128 but it has to be centered vertically/horizontally and optimized.

You can follow this tutorial on how to do it.

[canaleal]

I'm not gonna lie, this icon will be hard to convert into a plain svg.
Right now, all plain svgs should only have 1 path and 1 fill color as mentioned in the wiki. This svg has multiple.