dotpro.delete() cause an error with Angular9/TS3.7

[tmmschmit]

Hello, i was using your lib with Angular 8 and Typescript 3.5, but i've upgraded my app to Angular 9/Typescript 3.7 and now i have an error with dotprop.delete().

Look like it won't let me assign a Partial<> on my state anymore. 🤔