chore: ignore yarn cache

Author: sol-mocha

.gitignore

@@ -10,4 +10,9 @@ upgrade-authority.json
 .temp
 scratchpad.md
 drip-keypair.json
-rustc-ice-*.txt
+rustc-ice-*.txt
+
+.yarn/*
+!.yarn/releases
+!.yarn/plugins
+.pnp.*