Add Swift Algorithms as an explicit dependency (#217)

Explicitly depend on Swift-algorithms, rather indirectly through Vapor

Some users were running into issues compiling leaf against an older version of Vapor (pre 4.61.0)

Author: Joannis

Package.swift

@@ -12,7 +12,11 @@ let package = Package(
     ],
     dependencies: [
         .package(url: "https://github.com/vapor/leaf-kit.git", from: "1.3.1"),
+        
         .package(url: "https://github.com/vapor/vapor.git", from: "4.0.0"),
+        
+        // Swift collection algorithms
+        .package(url: "https://github.com/apple/swift-algorithms.git", from: "1.0.0"),
     ],
     targets: [
         .target(name: "Leaf", dependencies: [

Sources/Leaf/LeafEncoder.swift

@@ -1,4 +1,5 @@
 import LeafKit
+import Algorithms
 
 internal struct LeafEncoder {
     /// Use `Codable` to convert an (almost) arbitrary encodable type to a dictionary of key/``LeafData`` pairs