Swift 5.0 compatibility

OhhAuth.podspec

@@ -1,12 +1,14 @@
 Pod::Spec.new do |s|
   s.name         = "OhhAuth"
-  s.version      = "1.0.0"
+  s.version      = "1.1.0"
   s.summary      = "Pure Swift implementation of the OAuth 1.0 protocol as an easy to use extension for the URLRequest type. (RFC-5849)"
   s.authors      = "Markus Wanke"
   s.homepage     = "https://github.com/mw99/OhhAuth"
   s.license      = { :type => 'Apache 2.0', :file => 'LICENSE' }
   s.source       = { :git => "https://github.com/mw99/OhhAuth.git", :tag => s.version }
 
+  s.swift_version = '5'
+
   s.ios.deployment_target = '8.0'
   s.osx.deployment_target = '10.10'
   s.tvos.deployment_target = '9.0'

Package.swift

@@ -1,5 +1,13 @@
+// swift-tools-version:4.0
+
 import PackageDescription
 
 let package = Package(
-    name: "OhhAuth"
+    name: "OhhAuth",
+    products: [
+        .library(name: "OhhAuth", targets: ["OhhAuth"])
+    ],
+    targets: [
+        .target(name: "OhhAuth", path: ".")
+    ]
 )

Sources/OhhAuth.swift

@@ -23,7 +23,7 @@
 
 import Foundation
 
-open class OhhAuth
+public class OhhAuth
 {
     /// Tuple to represent signing credentials. (consumer as well as user credentials)
     public typealias Credentials = (key: String, secret: String)
@@ -41,7 +41,7 @@ open class OhhAuth
     ///   - userCredentials: user credentials (nil if this is a request without user association)
     ///
     /// - Returns: OAuth HTTP header entry for the Authorization field.
-    open static func calculateSignature(url: URL, method: String, parameter: [String: String],
+    static func calculateSignature(url: URL, method: String, parameter: [String: String],
         consumerCredentials cc: Credentials, userCredentials uc: Credentials?) -> String
     {
         typealias Tup = (key: String, value: String)
@@ -99,7 +99,7 @@ open class OhhAuth
     /// - Parameter paras: url-form parameters
     /// - Parameter encoding: used string encoding (default: .utf8)
     /// - Returns: correctly percentage encoded url-form parameters
-    open static func httpBody(forFormParameters paras: [String: String], encoding: String.Encoding = .utf8) -> Data?
+    static func httpBody(forFormParameters paras: [String: String], encoding: String.Encoding = .utf8) -> Data?
     {
         let trans: (String, String) -> String = { k, v in
             return rfc3986encode(k) + "=" + rfc3986encode(v)
@@ -154,7 +154,7 @@ public extension URLRequest
     ///   - paras: url-form parameters
     ///   - consumerCredentials: consumer credentials
     ///   - userCredentials: user credentials (nil if this is a request without user association)
-    public mutating func oAuthSign(method: String, urlFormParameters paras: [String: String],
+    mutating func oAuthSign(method: String, urlFormParameters paras: [String: String],
         consumerCredentials cc: OhhAuth.Credentials, userCredentials uc: OhhAuth.Credentials? = nil)
     {
         self.httpMethod = method.uppercased()
@@ -182,7 +182,7 @@ public extension URLRequest
     ///   - contentType: HTTP header "Content-Type" entry (default: nil)
     ///   - consumerCredentials: consumer credentials
     ///   - userCredentials: user credentials (nil if this is a request without user association)
-    public mutating func oAuthSign(method: String, body: Data? = nil, contentType: String? = nil,
+    mutating func oAuthSign(method: String, body: Data? = nil, contentType: String? = nil,
         consumerCredentials cc: OhhAuth.Credentials, userCredentials uc: OhhAuth.Credentials? = nil)
     {
         self.httpMethod = method.uppercased()