fix(fixture): updated api.github.com/get-root

BREAKING CHANGE: api.github.com/get-root has changed

```diff
[
   {
     response: {
+      label_search_url: "https://api.github.com/search/labels?q={query}&repository_id={repository_id}{&page,per_page}"
     }
     headers: {
-      content-length: "2039"
+      content-length: "2153"
     }
   }
 ]
```

scenarios/api.github.com/get-root/normalized-fixture.json

@@ -22,6 +22,7 @@
       "issue_search_url": "https://api.github.com/search/issues?q={query}{&page,per_page,sort,order}",
       "issues_url": "https://api.github.com/issues",
       "keys_url": "https://api.github.com/user/keys",
+      "label_search_url": "https://api.github.com/search/labels?q={query}&repository_id={repository_id}{&page,per_page}",
       "notifications_url": "https://api.github.com/notifications",
       "organization_repositories_url": "https://api.github.com/orgs/{org}/repos{?type,page,per_page,sort}",
       "organization_url": "https://api.github.com/orgs/{org}",
@@ -48,7 +49,7 @@
       "access-control-expose-headers": "ETag, Link, Location, Retry-After, X-GitHub-OTP, X-RateLimit-Limit, X-RateLimit-Remaining, X-RateLimit-Reset, X-OAuth-Scopes, X-Accepted-OAuth-Scopes, X-Poll-Interval, X-GitHub-Media-Type",
       "cache-control": "private, max-age=60, s-maxage=60",
       "connection": "close",
-      "content-length": "2039",
+      "content-length": "2153",
       "content-security-policy": "default-src 'none'",
       "content-type": "application/json; charset=utf-8",
       "date": "Tue, 10 Oct 2017 16:00:00 GMT",