readme: Use cropped image (#783)

README.md

@@ -1,5 +1,5 @@
 <div align="center">
-  <img height="170x" src="https://media.discordapp.net/attachments/889596381235392522/889979895860568114/anchor-radius.png?width=746&height=746" />
+  <img height="170x" src="https://media.discordapp.net/attachments/813444514949103658/890278520553603092/export.png?width=746&height=746" />
 
   <h1>Anchor</h1>