Implemented the UpdateCommand command in the executable target.

Executable/Sources/Commands/UpdateCommand.swift

@@ -0,0 +1,29 @@
+import ArgumentParser
+import ColibriLibrary
+
+extension Colibri {
+    struct Update: AsyncParsableCommand {
+        
+        // MARK: Properties
+        
+        static let configuration = CommandConfiguration(
+            commandName: "update-dependencies",
+            abstract: "Update package dependencies in a Hummingbird app",
+            helpNames: .shortAndLong,
+            aliases: ["update"]
+        )
+        
+        @OptionGroup var options: Options
+        
+        // MARK: Functions
+        
+        mutating func run() async throws {
+            let terminalService = TerminalService()
+
+            let updateDependencies = UpdateDependenciesTask(terminalService: terminalService)
+            
+            try await updateDependencies(at: options.locationURL)
+        }
+        
+    }
+}

Executable/Sources/Options/UpdateOptions.swift

@@ -0,0 +1,13 @@
+import ArgumentParser
+import ColibriLibrary
+
+extension Colibri.Update {
+    struct Options: ParsableArguments, Locationable {
+        
+        // MARK: Properties
+        
+        @Option(name: .shortAndLong)
+        var location: String?
+        
+    }
+}