Expose onForgotPassword [SDK-2632] (#673)

* Expose onForgotPassword

* Add unit test for the public API method

* Fix test

Lock/Lock.swift

@@ -250,6 +250,19 @@ public class Lock: NSObject {
         return self
     }
 
+    /**
+     Register a callback to be notified when a user requests a password reset.
+     The callback will yield the user identifier.
+
+     - parameter callback: called when a user requests a password reset.
+
+     - returns: Lock itself for chaining
+     */
+    public func onForgotPassword(callback: @escaping (String) -> Void) -> Lock {
+        self.observerStore.onForgotPassword = callback
+        return self
+    }
+
     /**
      Presents Lock from the given controller
 
@@ -277,7 +290,7 @@ public class Lock: NSObject {
         return self
     }
 
-        /// Lock's Bundle. Useful for getting bundled resources like images.
+    /// Lock's Bundle. Useful for getting bundled resources like images.
     public static var bundle: Bundle {
         return bundleForLock()
     }

LockTests/LockSpec.swift

@@ -176,6 +176,14 @@ class LockSpec: QuickSpec {
                 expect(executed) == true
             }
 
+            it("should register onForgotPassword callback") {
+                var email: String? = nil
+                let callback: (String) -> () = { email = $0 }
+                let _ = lock.onForgotPassword(callback: callback)
+                lock.observerStore.onForgotPassword("mail@mail.com")
+                expect(email) == "mail@mail.com"
+            }
+
             it("should register onPasswordless callback") {
                 var email: String? = nil
                 let callback: (String) -> () = { email = $0 }