update icon: postcss (original, original-wordmark, plain-wordmark)

[weh]

Double check these details before you open a PR

• PR does not match another non-stale PR currently opened

Features

• Replace plain with alias
• Optimize svgs

This PR closes NONE

Part of #2001

Notes

[canaleal]

Great work, LGTM!
By the way, I added a fill to plain-wordmark path to ensure it follows the same format as the other SVGs.

[Snailedlt]

Postcss-original has some weird artifacting that needs to be fixed:

Original wordmark looks good though:

[weh]

• fixed the icon (removed artifacts)
• rebased to current develop branch

@canaleal sorry, i think i flushed your changes with my force push, can you please check again

[Snailedlt]

@weh Although I love rebasing myself it's not really that useful in devicons, but it can sometimes be hurtful.
In general, try to use merge instead of rebase when fixing PRs, especially after someone has reviewed it since it makes it much easier to see what changed since their last review.

Also we don't really care about a clean git history on feature branches since they are squash-merged into develop anyways, so it always ends up being just 1 commit :)

[Snailedlt]

Nice, the artifacts are fixed! Excellent work!
However, like you said there are some changes that @canaleal suggested that are missing. I made some new suggestions to hopefully fix those :)

[lunatic-fox]

Another great work! 👍🏼
Thank you for this contribution! 🚀

[Snailedlt]

LGTM! ✔️
Looks Great! 💯 Thank you for another great PR! 🙇‍♂️