Lottie-ios: Fail to build app in Xcode 12

[ricardohochman]

Check these before submitting:

• [X] The issue doesn't involve an Unsupported Feature
• [X] This issue isn't related to another open issue

This issue is a:

• [ ] Non-Crashing Bug (Visual or otherwise)
• [ ] Crashing Bug
• [ ] Feature Request
• [X] Regression (Something that once worked, but doesn't work anymore)

Which Version of Lottie are you using?

Lottie 3.1.8

What Platform are you on?

• [ ] MacOS
• [X] iOS

What Language are you in?

• [X] Swift
• [ ] Objective-C

Expected Behavior

Project building successfully

Actual Behavior

Undefined symbols for architecture armv7:
  "type metadata for Swift._StringObject.Variant", referenced from:
      outlined init with take of Swift._StringObject.Variant in AnimationKeypathExtension.o
ld: symbol(s) not found for architecture armv7

Xcode Version 12.0 beta (12A6159)

[danl3v]

In beta 1, we found that substrings seem to have issues compiling. We could get it building by updating

func equalsKeypath(_ keyname: String) -> Bool - if you wrap the prefix and suffix methods with String(), we were then able to build

[danl3v]

Here are our changes: https://github.com/airbnb/lottie-ios/pull/1215

[m760622]

I fixed it by going to the Build Settings * for *Lottie-ios Deployment and changed the iOS Deployment Target to iOS 13

[danl3v]

This is fixed in Xcode 12 beta 4 and the PR can be reverted