Update dependencies to use semantic versioning

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Co-Authored-By: Claude <[email protected]>

Author: coenttb

Package.swift

@@ -23,8 +23,8 @@ let package = Package(
         .library(name: .rfc5322, targets: [.rfc5322]),
     ],
     dependencies: [
-        .package(url: "https://github.com/swift-web-standards/swift-rfc-1123.git", branch: "main"),
-        .package(url: "https://github.com/swift-web-standards/swift-rfc-5321.git", branch: "main"),
+        .package(url: "https://github.com/swift-web-standards/swift-rfc-1123.git", from: "0.0.1"),
+        .package(url: "https://github.com/swift-web-standards/swift-rfc-5321.git", from: "0.0.1"),
     ],
     targets: [
         .target(