Fix SPM building issue.

- upgrade SPM tool version to current.
- Save 5.0 as version specific one.
- exclude js files for macOS version.

Author: yaroslavyaroslav

Package.swift

@@ -29,6 +29,7 @@ let package = Package(
     ],
     targets: [
         .target(name: "secp256k1"),
+
         .target(
             name: "web3swift",
             dependencies: ["BigInt", "secp256k1", "PromiseKit", "Starscream", "CryptoSwift"],