Change logo to PNG with transparent round corners (#137)

* Change logo to PNG with transparent round corners

Too big. :(

* Optimize PNG logo

From 519K to 214K.

* Make the background really transparent

---------

Co-authored-by: Khaled Hosny <khaled@aliftype.com>

Author: behdad

README.md

@@ -1,7 +1,7 @@
 # harfbuzzjs
 
 <div align="center">
-<p><img src="logo.jpg" alt="harfbuzzjs Logo" width="256" align="center"/></p>
+<p><img src="logo.png" alt="harfbuzzjs Logo" width="256" align="center"/></p>
 
 [![Build](https://github.com/harfbuzz/harfbuzzjs/actions/workflows/build.yml/badge.svg)](https://github.com/harfbuzz/harfbuzzjs/actions/workflows/build.yml)
 [![NPM Version](https://img.shields.io/npm/v/harfbuzzjs)](https://www.npmjs.com/package/harfbuzzjs)