Bump vant from 1.6.28 to 2.2.14

Bumps [vant](https://github.com/youzan/vant) from 1.6.28 to 2.2.14.
- [Release notes](https://github.com/youzan/vant/releases)
- [Commits](https://github.com/youzan/vant/compare/v1.6.28...v2.2.14)

Signed-off-by: dependabot[bot] <support@github.com>

@@ -19,7 +19,7 @@
     "fastclick": "^1.0.6",
     "lib-flexible": "^0.3.2",
     "normalize.css": "7.0.0",
-    "vant": "^1.6.19",
+    "vant": "^2.2.14",
     "vue": "2.6.10",
     "vue-router": "3.0.6",
     "vuex": "3.1.0"