fixed 展开已选择项的所有父节点，并且居中显示，方便修改操作；搜索模式下展开已选项

   @varlamov88 [Expand parent nodes of selected item. Scroll menu to selected item](riophae#310)

   使用选项： scrollPositionOnCenter = true

```
   <treeselect
            v-model="orgCode"
            :clearable="true"
            :scrollPositionOnCenter="true"
            :default-expand-level="0"
          />
```

package.json

@@ -24,7 +24,7 @@
     "testonly": "npm run cleanup-cov && karma start test/unit/karma.config.js --single-run",
     "test": "npm run testonly",
     "pretest": "npm run lint",
-    "lint:js": "eslint --ext .js --ext .vue --cache --cache-location node_modules/.cache/eslint .",
+    "lint:js": "eslint --ext .js --ext .vue --cache --cache-location node_modules/.cache/eslint --rule 'no-console: 2' .",
     "lint:css": "stylelint '**/*.less'",
     "lint": "npm run lint:js && npm run lint:css",
     "verify-builds": "size-limit && node build/verify-builds.js",