fix: timeline format labels funtion Date params to Moment type fix

Author: minsgy

docs/timeline/index.html

@@ -668,8 +668,8 @@ <h2 id="Configuration_Options">Configuration Options</h2>
         You can also use a function format for each label. The function accepts as arguments the date, scale and step in that order, and expects to return a string for the label.
 
         <pre class="prettyprint lang-js">function format({
-  minorLabels: Function(date: Date, scale: Number, step: Number),
-  majorLabels: Function(date: Date, scale: Number, step: Number)
+  minorLabels: Function(date: Moment, scale: Number, step: Number),
+  majorLabels: Function(date: Moment, scale: Number, step: Number)
 }</pre>
       </td>
     </tr>

types/index.d.ts

@@ -144,7 +144,7 @@ export interface TimelineEditableOption {
   overrideItems?: boolean;
 }
 
-export type TimelineFormatLabelsFunction = (date: Date, scale: string, step: number) => string;
+export type TimelineFormatLabelsFunction = (date: Moment, scale: string, step: number) => string;
 
 export interface TimelineFormatLabelsOption {
   millisecond?: string;