deps: `minreq` required only for wallet

Cargo.toml

@@ -16,7 +16,7 @@ description = "Cashu rust wallet and mint library"
 [features]
 default = ["mint", "wallet"]
 mint = []
-wallet = []
+wallet = ["minreq"]
 
 [dependencies]
 base64 = "0.21.0"
@@ -25,7 +25,7 @@ bitcoin_hashes = "0.12.0"
 hex = "0.4.3"
 k256 = { version = "0.13.1", features=["arithmetic"] }
 lightning-invoice = { version = "0.23.0", features=["serde"] }
-minreq = { version = "2.7.0", features = ["json-using-serde", "https"] } 
+minreq = { version = "2.7.0", optional = true, features = ["json-using-serde", "https"] } 
 rand = "0.8.5"
 getrandom = { version = "0.2", features = ["js"] }
 serde = { version = "1.0.160", features = ["derive"]}