Add logo

README.md

@@ -1,4 +1,9 @@
-# BitcoinJS (bitcoinjs-lib)
+<img src="./logo/Bitcoin.js-transparent.png" alt="BitcoinJS kawaii logo" width="50%" />
+
+(Logo by [@sawaratsuki1004](https://x.com/sawaratsuki1004))
+
+([LICENSE for the logo is on SAWARATSUKI Github repo](https://github.com/SAWARATSUKI/KawaiiLogos/blob/main/README_EN.md))
+
 [![Github CI](https://github.com/bitcoinjs/bitcoinjs-lib/actions/workflows/main_ci.yml/badge.svg)](https://github.com/bitcoinjs/bitcoinjs-lib/actions/workflows/main_ci.yml) [![NPM](https://img.shields.io/npm/v/bitcoinjs-lib.svg)](https://www.npmjs.org/package/bitcoinjs-lib) [![code style: prettier](https://img.shields.io/badge/code_style-prettier-ff69b4.svg?style=flat-square)](https://github.com/prettier/prettier)
 
 A javascript Bitcoin library for node.js and browsers. Written in TypeScript, but committing the JS files to verify.

logo/LICENSE.md

@@ -0,0 +1,3 @@
+# LICENSE
+
+Please see the license here: [https://github.com/SAWARATSUKI/KawaiiLogos/blob/main/README_EN.md](https://github.com/SAWARATSUKI/KawaiiLogos/blob/main/README_EN.md)