Use native keyboard while typing pin code

Device&OS:Iphone6s IOS12.1.2

Hello, I’ve installed Gboard(google keyboard) on my mobile. Sometimes when I open bitwarden, it will shows a digital keyboard from Gboard instead of the native one. I think there are more users maybe using different 3rd party input apps, so to make it more secure, would you please make it force to use native keyboard while typing pin code, not depending on current input method? or bitwarden can go with its own digital keyboard? Thanks!