make children required in ProviderProps

Author: kingdaro

src/index.d.ts

@@ -9,7 +9,7 @@ export type Context<T> = {
 
 export type ProviderProps<T> = {
  value: T;
- children?: React.ReactNode;
+ children: React.ReactNode;
 };
 
 export type ConsumerProps<T> = {