chore: update version to 1.0.2 and improve chapter plugin functionality

- Bump version from 1.0.1 to 1.0.2 in package.json.
- Refactor index.js to remove unused variables and simplify event handling.
- Enhance title display logic in the chapter plugin for better user experience.
- Update styles in style.less for smoother transitions and improved visibility of chapter titles.

packages/artplayer-plugin-chapter/package.json

@@ -1,6 +1,6 @@
 {
   "name": "artplayer-plugin-chapter",
-  "version": "1.0.1",
+  "version": "1.0.2",
   "description": "chapter plugin for ArtPlayer",
   "author": "Harvey Zack <laozhaochaguan@gmail.com>",
   "license": "MIT",