Edit Discord badge. (#1954)

Add white Discord logo. Label the badge as "Discord". Use the official Discord logo's color value of 5865F2.

README.md

@@ -7,7 +7,7 @@
 </h1>
 
 <p align="center">
-  <a href="https://discord.gg/ZegqCBr"><img src="https://img.shields.io/discord/612704110008991783" alt="discord"></a>
+  <a href="https://discord.gg/ZegqCBr"><img src="https://img.shields.io/discord/612704110008991783?logo=discord&logoColor=white&label=Discord&color=5865F2" alt="discord"></a>
   <a href="https://github.com/standard/standard/actions/workflows/test-external.yml"><img src="https://github.com/standard/standard/actions/workflows/test-external.yml/badge.svg?branch=master" alt="External tests"></a>
   <a href="https://github.com/standard/standard/actions/workflows/test-internal.yml"><img src="https://github.com/standard/standard/actions/workflows/test-internal.yml/badge.svg?branch=master" alt="Internal tests"></a>
   <a href="https://github.com/standard/standard/actions?query=workflow%3A%22Old+test%22"><img src="https://github.com/standard/standard/workflows/Old%20test/badge.svg" alt="status badge old Node test"></a>