removing syntax typo in readme.md (#2729)

README.md

@@ -108,7 +108,7 @@ Once you have your Swift package set up, adding Alamofire as a dependency is as
 
 ```swift
 dependencies: [
-    .package(url: "https://github.com/Alamofire/Alamofire.git", from: "5.0.0-beta.2"))
+    .package(url: "https://github.com/Alamofire/Alamofire.git", from: "5.0.0-beta.2")
 ]
 ```