v3.0.0

Use CocoaPods in iOS - this should fix build issues with XCode 10.2 and Swift 5.

OBS! This is a breaking version that drops support for manual linking on iOS.

The reasoning behind this is that there's historically been issues with building manually linked projects every single time a new version of XCode and/or Swift was released. Using CocoaPods is a safer alternative to linking the native libraries this library depends on, which will hopefully be much less painful in the future. Once properly set up it will automatically fix issues with signing, linking and bitcode generation.

CocoaPods is also (arguably) the current de-facto standard way of integrating dependencies on iOS and is much more flexible than manual linking.

It is regrettable to drop support for manual linking and PR's for this support is much appreciated, we can however not continue supporting it any longer due to the amount of man hours needed every time a new version of XCode is released.

Upgrade instructions

If you've previously linked this library manually, you'll need to manually reverse the process within XCode:

1. Delete Zip.framework and iOSDFULibrary.framework from your file system
2. In XCode remove the references to the .framework files
3. In XCode remove the reference to RNNordicDfu.xcodeproj
4. In XCode under Build Settings > Search Paths > Framework Search Paths, remove the manually added framework search path
5. In XCode under Build Settings > Search Paths > Header Search Paths, remove the manually added header search path
6. Completely clean the project, including Derived Data

After this you should be able to follow the installation instructions and build the project.