Update ERRATA.md

Author: evanp

ERRATA.md

@@ -80,3 +80,24 @@ This document includes errata for the [Activity Streams](https://www.w3.org/TR/a
   - Unlike `latitude` and `longitude`, the domain of the `altitude` term is the `Object` type. The `altitude` term should be included in the list of properties of an `Object`. Because `altitude` is primarily documented as a property of a `Place`, publishers should not include `altitude` on objects that are not of type `Place`, and consumers should accept objects with this property that aren't of type `Place`.
 
   - The domain of the `attributedTo` property is both `Link` and `Object`. `attributedTo` should be included in the list of properties of a `Link`.
+
+  - Example 102 is missing a `type` property on the `Link` value of the `url` property. For clarity, the example should read:
+
+  ```json
+  {
+  "@context": "https://www.w3.org/ns/activitystreams",
+  "type": "Video",
+  "name": "Cool New Movie",
+  "duration": "PT2H30M",
+  "preview": {
+    "type": "Video",
+    "name": "Trailer",
+    "duration": "PT1M",
+    "url": {
+      "type": "Link",
+      "href": "http://example.org/trailer.mkv",
+      "mediaType": "video/mkv"
+    }
+  }
+}
+```