Fix: missing type definition (#591)

The type definition of the clear(opts?: { silent: boolean }) method was added.

src/datepicker.d.ts

@@ -128,7 +128,7 @@ declare class AirDatepicker<E extends HTMLElement = HTMLInputElement> {
     prev: () => void
     selectDate: (date: AirDatepickerDate | AirDatepickerDate[], opts?: {updateTime?: boolean, silent?: boolean}) => void
     unselectDate: (date: AirDatepickerDate) => void
-    clear: () => void
+    clear: (opts?: {silent?: boolean}) => void
     formatDate: (date: AirDatepickerDate, format: string) => string
     destroy: () => void
     update: (newOpts?: AirDatepickerOptions) => void