Switch to 21-DOT-DEV/swift-secp256k1 and fix empty hex parsing

- Switch secp256k1 dependency to 21-DOT-DEV/swift-secp256k1 (exact 0.12.2)
- Fix BigUInt, BigInt, Int hex initializers to return 0 for empty strings
- Update resolved dependencies

Author: dioKaratzas

Package.resolved

@@ -15,7 +15,7 @@ let package = Package(
     dependencies: [
         .package(url: "https://github.com/attaswift/BigInt", from: "5.3.0"),
         .package(url: "https://github.com/iwill/generic-json-swift", .upToNextMajor(from: "2.0.2")),
-        .package(url: "https://github.com/GigaBitcoin/secp256k1.swift.git", .upToNextMajor(from: "0.6.0")),
+        .package(url: "https://github.com/21-DOT-DEV/swift-secp256k1", exact: "0.12.2"),
         .package(url: "https://github.com/vapor/websocket-kit.git", from: "2.16.1"),
         .package(url: "https://github.com/apple/swift-log.git", from: "1.6.4")
     ],
@@ -29,7 +29,7 @@ let package = Package(
                     .target(name: "Internal_CryptoSwift_PBDKF2"),
                     "BigInt",
                     .product(name: "GenericJSON", package: "generic-json-swift"),
-                    .product(name: "secp256k1", package: "secp256k1.swift"),
+                    .product(name: "secp256k1", package: "swift-secp256k1"),
                     .product(name: "WebSocketKit", package: "websocket-kit"),
                     .product(name: "Logging", package: "swift-log")
                 ],

Package.swift

@@ -15,7 +15,7 @@ let package = Package(
     dependencies: [
         .package(url: "https://github.com/attaswift/BigInt", from: "5.3.0"),
         .package(url: "https://github.com/iwill/generic-json-swift", .upToNextMajor(from: "2.0.2")),
-        .package(url: "https://github.com/GigaBitcoin/secp256k1.swift.git", .upToNextMajor(from: "0.6.0")),
+        .package(url: "https://github.com/21-DOT-DEV/swift-secp256k1", exact: "0.12.2"),
         .package(url: "https://github.com/vapor/websocket-kit.git", from: "2.16.1"),
         .package(url: "https://github.com/apple/swift-log.git", from: "1.6.4")
     ],
@@ -29,7 +29,7 @@ let package = Package(
                     .target(name: "Internal_CryptoSwift_PBDKF2"),
                     "BigInt",
                     .product(name: "GenericJSON", package: "generic-json-swift"),
-                    .product(name: "secp256k1", package: "secp256k1.swift"),
+                    .product(name: "secp256k1", package: "swift-secp256k1"),
                     .product(name: "WebSocketKit", package: "websocket-kit"),
                     .product(name: "Logging", package: "swift-log")
                 ],

Package@swift-6.1.swift

@@ -8,7 +8,12 @@ import Foundation
 
 public extension BigUInt {
     init?(hex: String) {
-        self.init(hex.web3.noHexPrefix.lowercased(), radix: 16)
+        let stripped = hex.web3.noHexPrefix.lowercased()
+        if stripped.isEmpty {
+            self.init(0)
+        } else {
+            self.init(stripped, radix: 16)
+        }
     }
 }
 
@@ -24,13 +29,23 @@ public extension Web3Extensions where Base == BigUInt {
 
 public extension BigInt {
     init?(hex: String) {
-        self.init(hex.web3.noHexPrefix.lowercased(), radix: 16)
+        let stripped = hex.web3.noHexPrefix.lowercased()
+        if stripped.isEmpty {
+            self.init(0)
+        } else {
+            self.init(stripped, radix: 16)
+        }
     }
 }
 
 public extension Int {
     init?(hex: String) {
-        self.init(hex.web3.noHexPrefix, radix: 16)
+        let stripped = hex.web3.noHexPrefix
+        if stripped.isEmpty {
+            self.init(0)
+        } else {
+            self.init(stripped, radix: 16)
+        }
     }
 }