Update dev-dependencies

Author: wooorm

README.md

@@ -51,7 +51,7 @@ Yields:
   map: 
    { type: 'list',
      ordered: false,
-     children: [ { type: 'listItem', loose: true, children: [Object] } ] } }
+     children: [ { type: 'listItem', loose: true, children: [Array] } ] } }
 ```
 
 ## API

lib/index.js

@@ -27,7 +27,7 @@ function toc(node, options) {
     var result = search(node, heading, settings.maxDepth || 6);
     var map = result.map;
 
-    result.map = map.length ? contents(map, settings.tight) : null;
+    result.map = map.length === 0 ? null : contents(map, settings.tight);
 
     /* No given heading */
     if (!heading) {

package.json

@@ -42,7 +42,7 @@
     "browserify": "^16.2.1",
     "esmangle": "^1.0.1",
     "istanbul": "^0.4.4",
-    "remark-attr": "^0.6.2",
+    "remark-attr": "^0.7.0",
     "remark": "^10.0.0",
     "remark-cli": "^6.0.0",
     "remark-comment-config": "^5.0.0",
@@ -52,7 +52,7 @@
     "remark-usage": "^6.0.0",
     "remark-validate-links": "^7.0.0",
     "tape": "^4.6.0",
-    "xo": "^0.21.1"
+    "xo": "^0.23.0"
   },
   "xo": {
     "space": 4,