Fix Xcode 14 compiler warning

[ddaddy]

Description

protocol class has been deprecated and replaced with AnyObject

Type of change

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

How Has This Been Tested?

Successful compilation with the following

• Test iOS 14
• Test iOS 13
• Test iOS 12

Test Configuration

• Xcode Versions: [13.3 & 14.0]

Checklist:

• My code follows the style guidelines of this project
• My code does not break backwards compatibility with earlier versions of PulleyLib
• My code is fully functional with all supported device sizes and orientations
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• 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
• I have tested and can prove my fix is effective or that my feature works