Fix Xcode 14 compiler warning

[ddaddy]

Description

protocol class has been deprecated and replaced with AnyObject

Type of change

• [x] Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

Successful compilation with the following

• [x] Test iOS 14
• [x] Test iOS 13
• [x] Test iOS 12

Test Configuration

• Xcode Versions: [13.3 & 14.0]

Checklist:

• [x] My code follows the style guidelines of this project
• [x] My code does not break backwards compatibility with earlier versions of PulleyLib
• [x] My code is fully functional with all supported device sizes and orientations
• [x] I have performed a self-review of my own code
• [ ] I have commented my code, particularly in hard-to-understand areas
• [x] I have checked that my code does not break the behavior of the Sample/Demo app
• [ ] I have made corresponding changes to the documentation
• [ ] My changes generate no new warnings
• [x] I have tested and can prove my fix is effective or that my feature works