chore: bump cashu to 0.20 for pydantic v2 compat

pyproject.toml

@@ -13,7 +13,7 @@ dependencies = [
     "greenlet>=3.2.1",
     "alembic>=1.13",
     "python-json-logger>=2.0.0",
-    "cashu",
+    "cashu>=0.20",
     "secp256k1",
     "marshmallow>=3.13,<4.0",
     "websockets>=12.0",

uv.lock

@@ -2424,7 +2424,7 @@ dev = [
 requires-dist = [
     { name = "aiosqlite", specifier = ">=0.20" },
     { name = "alembic", specifier = ">=1.13" },
-    { name = "cashu" },
+    { name = "cashu", specifier = ">=0.20" },
     { name = "fastapi", extras = ["standard"], specifier = ">=0.115" },
     { name = "greenlet", specifier = ">=3.2.1" },
     { name = "httpx", extras = ["socks"], specifier = ">=0.25.2" },