Change Swift version to 3.2

.swift-version

@@ -1 +1 @@
-3.1
+3.2

.travis.yml

@@ -1,5 +1,5 @@
 language: swift
-osx_image: xcode8.3
+osx_image: xcode9
 script:
   - set -o pipefail && xcodebuild test -scheme CSV-macOS
 after_success:

CSV.xcodeproj/project.pbxproj

@@ -886,7 +886,7 @@
 				PRODUCT_NAME = CSV;
 				SDKROOT = macosx;
 				SKIP_INSTALL = YES;
-				SWIFT_VERSION = 4.0;
+				SWIFT_VERSION = 3.0;
 			};
 			name = Debug;
 		};
@@ -909,7 +909,7 @@
 				SDKROOT = macosx;
 				SKIP_INSTALL = YES;
 				SWIFT_OPTIMIZATION_LEVEL = "-Owholemodule";
-				SWIFT_VERSION = 4.0;
+				SWIFT_VERSION = 3.0;
 			};
 			name = Release;
 		};

Package.swift

@@ -2,6 +2,5 @@ import PackageDescription
 
 let package = Package(
     name: "CSV",
-    targets: [],
-    dependencies: []
+    swiftLanguageVersions: [3, 4]
 )