Update dependency pointycastle to v4

renovate[bot] · web-flow · commit 405cc096c078 · 2026-04-08T20:38:05.000Z
diff --git a/pubspec.yaml b/pubspec.yaml
@@ -17,7 +17,7 @@ dependencies:
   decimal: ^3.0.1
   bip32: ^2.0.0
   convert: ^3.1.1
-  pointycastle: ^3.6.2
+  pointycastle: ^4.0.0
   http: ^1.0.0
   meta: ^1.12.0
 
