Update readme for 7.0.0 release (#270)

README.md

@@ -76,10 +76,8 @@ Creating a 'Sign in with Google' button in SwiftUI can be as simple as this:
 
 ```
 GoogleSignInButton {
-  GIDSignIn.sharedInstance.signIn(
-    with: configuration, 
-    presenting: yourViewController) { user, error in
-      // check `error`; do something with `user`
+  GIDSignIn.sharedInstance.signIn(withPresenting: yourViewController) { signInResult, error in
+      // check `error`; do something with `signInResult`
   }
 }
 ```
@@ -111,10 +109,8 @@ that it will be available for use in AppKit.
 
 ```
 let signInButton = GoogleSignInButton {
-  GIDSignIn.sharedInstance.signIn(
-    with: configuration, 
-    presenting: yourViewController) { user, error in
-      // check `error`; do something with `user`
+  GIDSignIn.sharedInstance.signIn(withPresenting: yourViewController) { signInResult, error in
+      // check `error`; do something with `signInResult`
   }
 }
 let hostedButton = NSHostingView(rootView: signInButton)