chore: update value type (#718)

Author: zombieJ

src/PickerInput/RangePicker.tsx

@@ -56,7 +56,7 @@ export interface BaseRangePickerProps<DateType extends object>
   separator?: React.ReactNode;
 
   // Value
-  value?: RangeValueType<DateType>;
+  value?: RangeValueType<DateType> | null;
   defaultValue?: RangeValueType<DateType>;
   onChange?: (dates: RangeValueType<DateType>, dateStrings: [string, string]) => void;
   onCalendarChange?: (

src/PickerInput/SinglePicker.tsx

@@ -45,7 +45,7 @@ export interface BasePickerProps<DateType extends object = any>
   maxTagCount?: number | 'responsive';
 
   // Value
-  value?: DateType | DateType[];
+  value?: DateType | DateType[] | null;
   defaultValue?: DateType | DateType[];
   onChange?: (date: DateType | DateType[], dateString: string | string[]) => void;
   onCalendarChange?: (