Update the availability annotations.

Author: andersio

Sources/CombineInteroperability/FromCombine.swift

@@ -1,6 +1,7 @@
 #if canImport(Combine)
 import Combine
 
+@available(macOS 10.15, iOS 13.0, tvOS 13.0, macCatalyst 13.0, watchOS 6.0, *)
 extension Publisher {
 	public func producer() -> SignalProducer<Output, Failure> {
 		return SignalProducer { observer, lifetime in

Sources/CombineInteroperability/ToCombine.swift

@@ -2,21 +2,13 @@
 import Combine
 
 extension SignalProducerConvertible {
-	@available(macOS 10.15, *)
-	@available(iOS 13.0, *)
-	@available(tvOS 13.0, *)
-	@available(macCatalyst 13.0, *)
-	@available(watchOS 6.0, *)
+	@available(macOS 10.15, iOS 13.0, tvOS 13.0, macCatalyst 13.0, watchOS 6.0, *)
 	public func publisher() -> ProducerPublisher<Value, Error> {
 		ProducerPublisher(base: producer)
 	}
 }
 
-@available(macOS 10.15, *)
-@available(iOS 13.0, *)
-@available(tvOS 13.0, *)
-@available(macCatalyst 13.0, *)
-@available(watchOS 6.0, *)
+@available(macOS 10.15, iOS 13.0, tvOS 13.0, macCatalyst 13.0, watchOS 6.0, *)
 public struct ProducerPublisher<Output, Failure: Swift.Error>: Publisher {
 	public let base: SignalProducer<Output, Failure>
 

Sources/CombineInteroperability/Utilities.swift

@@ -2,24 +2,28 @@
 import Combine
 
 extension Lifetime {
+	@available(macOS 10.15, iOS 13.0, tvOS 13.0, macCatalyst 13.0, watchOS 6.0, *)
 	@discardableResult
 	public static func += <C: Cancellable>(lhs: Lifetime, rhs: C) -> Disposable? {
 		lhs.observeEnded(rhs.cancel)
 	}
 }
 
+@available(macOS 10.15, iOS 13.0, tvOS 13.0, macCatalyst 13.0, watchOS 6.0, *)
 extension AnyDisposable: Cancellable {
 	public func cancel() {
 		dispose()
 	}
 }
 
+@available(macOS 10.15, iOS 13.0, tvOS 13.0, macCatalyst 13.0, watchOS 6.0, *)
 extension SerialDisposable: Cancellable {
 	public func cancel() {
 		dispose()
 	}
 }
 
+@available(macOS 10.15, iOS 13.0, tvOS 13.0, macCatalyst 13.0, watchOS 6.0, *)
 extension CompositeDisposable: Cancellable {
 	public func cancel() {
 		dispose()