Build failure with Xcode 11.3

The README does not call out if a specific Xcode version is expected. I am trying to build with Xcode 11.3 but end with the following errors, which all seem to be around the `MXKeyVerification` object?

Is the _develop_ branch unstable? Should I build from a tagged release?

```
/Users/stefan/Projects/riot-ios/Riot/SupportingFiles/Riot-Bridging-Header.h:17:9: note: in file included from /Users/stefan/Projects/riot-ios/Riot/SupportingFiles/Riot-Bridging-Header.h:17:
#import "AppDelegate.h"
^
/Users/stefan/Projects/riot-ios/Riot/AppDelegate.h:140:48: error: expected a type
- (BOOL)presentIncomingKeyVerificationRequest:(MXKeyVerificationRequest*)incomingKeyVerificationRequest
^
/Users/stefan/Projects/riot-ios/Riot/SupportingFiles/Riot-Bridging-Header.h:18:9: note: in file included from /Users/stefan/Projects/riot-ios/Riot/SupportingFiles/Riot-Bridging-Header.h:18:
#import "RoomBubbleCellData.h"
^
/Users/stefan/Projects/riot-ios/Riot/Modules/Room/CellData/RoomBubbleCellData.h:80:30: error: unknown type name 'MXKeyVerification'
@property(nonatomic, strong) MXKeyVerification *keyVerification;
^
/Users/stefan/Projects/riot-ios/Riot/SupportingFiles/Riot-Bridging-Header.h:18:9: note: in file included from /Users/stefan/Projects/riot-ios/Riot/SupportingFiles/Riot-Bridging-Header.h:18:
#import "RoomBubbleCellData.h"
^
/Users/stefan/Projects/riot-ios/Riot/Modules/Room/CellData/RoomBubbleCellData.h:80:1: error: property with 'retain (or strong)' attribute must be of object type
@property(nonatomic, strong) MXKeyVerification *keyVerification;
^
3 errors generated.
:0: error: failed to emit precompiled header '/Users/stefan/Library/Developer/Xcode/DerivedData/Riot-fqqbkfssnvsqzidgbrpdnigpfpwh/Build/Intermediates.noindex/PrecompiledHeaders/Riot-Bridging-Header-swift_3O9IWK8N49TCP-clang_3VXJE28F1NZ5E.pch' for bridging header '/Users/stefan/Projects/riot-ios/Riot/SupportingFiles/Riot-Bridging-Header.h'
```