Update TextFieldEffects.swift

Fixes issues to build with Swift 4

Author: hyerra

TextFieldEffects/TextFieldEffects/TextFieldEffects.swift

@@ -110,14 +110,14 @@ open class TextFieldEffects : UITextField {
  /**
  The textfield has started an editing session.
  */
- open func textFieldDidBeginEditing() {
+ @objc open func textFieldDidBeginEditing() {
  animateViewsForTextEntry()
  }
 
  /**
  The textfield has ended an editing session.
  */
- open func textFieldDidEndEditing() {
+ @objc open func textFieldDidEndEditing() {
  animateViewsForTextDisplay()
  }