Update for Xcode 11.4 and for iOS 13.4

Author: Rad Azzouz

README.md

@@ -102,7 +102,7 @@ doing. If you are unsure, please use CocoaPods or Carthage instead.
 First, build the PDFXKit framework:
 
 * Clone `git@github.com:PSPDFKit/PDFXKit.git`
-* Replace `COCOAPODS_KEY` with your key and download the following the fat frameworks from here: https://customers.pspdfkit.com/cocoapods/COCOAPODS_KEY/pspdfkit/9.2.1.zip
+* Replace `COCOAPODS_KEY` with your key and download the following the fat frameworks from here: https://customers.pspdfkit.com/cocoapods/COCOAPODS_KEY/pspdfkit/latest.zip
 * Extract the zip file you downloaded and copy `PSPDFKit.framework` and `PSPDFKitUI.framework` into `PDFXKit/Frameworks`
 * Open the terminal and `cd` into the `PDFXKit` directory
 * Run `rake compile`
@@ -172,7 +172,7 @@ annotated with the `PDFX_NOT_IMPLEMENTED_PRIORITY_...` and
 If you want to work on PDFXKit, perform the following steps:
 
 * Clone `git@github.com:PSPDFKit/PDFXKit.git`
-* Replace `COCOAPODS_KEY` with your key and download the following the fat frameworks from here: https://customers.pspdfkit.com/cocoapods/COCOAPODS_KEY/pspdfkit/9.2.1.zip
+* Replace `COCOAPODS_KEY` with your key and download the following the fat frameworks from here: https://customers.pspdfkit.com/cocoapods/COCOAPODS_KEY/pspdfkit/latest.zip
 * Extract the zip file you downloaded and copy `PSPDFKit.framework` and `PSPDFKitUI.framework` into `PDFXKit/Frameworks`
 * Open `PDFXKit.xcodeproj` in Xcode
 * Build & Run `PDFXKitExample` (iOS)

Rakefile

@@ -51,8 +51,8 @@ VERBOSE = ENV['verbose'] || false
 
 # ------------------------------------------------------------- Constants ------
 
-SDK_SIM = "iphonesimulator13.2"
-SDK_IOS = "iphoneos13.2"
+SDK_SIM = "iphonesimulator13.4"
+SDK_IOS = "iphoneos13.4"
 XCODE_FLAGS = "-configuration Release -scheme PDFXKit -derivedDataPath \"#{DIRECTORY}/Xcode\""
 
 # ---------------------------------------------------------------- Colors ------