Fixed a few errors related to older macOS versions

Package.swift

@@ -5,7 +5,7 @@ import PackageDescription
 
 let package = Package(
     name: "TUSKit",
-    platforms: [.iOS(.v10), .macOS(.v10_10)],
+    platforms: [.iOS(.v10), .macOS(.v10_11)],
     products: [
         // Products define the executables and libraries a package produces, and make them visible to other packages.
         .library(

Sources/TUSKit/TUSClient.swift

@@ -107,10 +107,15 @@ public final class TUSClient {
                 storageDirectory: URL? = nil, chunkSize: Int = 500 * 1024,
                 supportedExtensions: [TUSProtocolExtension] = [.creation]) throws {
 
-        if sessionConfiguration.sessionSendsLaunchEvents == false {
+        if #available(iOS 7.0, macOS 11.0, *) {
+          if sessionConfiguration.sessionSendsLaunchEvents == false {
             print("TUSClient warning: initializing with a session configuration that's not suited for background uploads.")
+          }
+        } else {
+          print("TUSClient warning: Cannot verify URLSession background configuration; Background sessions are most likely not supported on your target OS.")
         }
 
+
         let scheduler = Scheduler()
         self.sessionIdentifier = sessionIdentifier
         self.api = TUSAPI(sessionConfiguration: sessionConfiguration)

TUSKit.podspec

@@ -7,7 +7,7 @@
 
 Pod::Spec.new do |s|
   s.name             = 'TUSKit'
-  s.version          = '3.2'
+  s.version          = '3.2.0'
   s.summary          = 'TUSKit client in Swift'
   s.swift_version = '5.0'
 
@@ -28,8 +28,8 @@ Swift client for https://tus.io called TUSKit. Mac and iOS compatible.
   s.source           = { :git => 'https://github.com/tus/TUSKit.git', :tag => s.version.to_s }
   s.platform         = :ios
 
-  s.ios.deployment_target = '9.0'
-  s.osx.deployment_target  = '10.9'
+  s.ios.deployment_target = '10.0'
+  s.osx.deployment_target  = '10.11'
 
   s.source_files = 'Sources/TUSKit/**/*'