Issue While migrating to swift 4.2 #99

Using Current UXMPDFKit Version 0.7.2 for swift 3. But Cant Upgrade to swift 4.2 with version 0.7.3

Bugs While Migrating to swift 4.2

1. CocoaPods could not find compatible versions for pod "UXMPDFKit"
2. CocoaPods could not find compatible versions for pod "UXMPDFKit" —>
   1.CocoaPods could not find compatible versions for pod "UXMPDFKit": In Podfile: UXMPDFKit (~> 0.7.3)

Steps to Reproduce (for bugs)

1. Try to Update source repo that hosts the Podspec

Your Environment

• iOS Version: 11
• Xcode Version: 10.1
• Swift Version: 4.2