Bumped tvOS to 13.

Author: bsneed

Package.swift

@@ -8,7 +8,7 @@ let package = Package(
     platforms: [
         .macOS("10.15"),
         .iOS("13.0"),
-        .tvOS("12.0")
+        .tvOS("13.0")
     ],
     products: [
         // Products define the executables and libraries a package produces, and make them visible to other packages.