Update apns.md (#943)

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docs/advanced/apns.md

@@ -18,12 +18,12 @@ let package = Package(
  name: "my-app",
  dependencies: [
  // Other dependencies...
- .package(url: "https://github.com/vapor/apns.git", from: "5.0.0"),
+ .package(url: "https://github.com/vapor/apns.git", from: "4.0.0"),
  ],
  targets: [
  .target(name: "App", dependencies: [
  // Other dependencies...
- .product(name: "APNS", package: "apns")
+ .product(name: "VaporAPNS", package: "apns")
  ]),
  // Other targets...
  ]