fix(deps): update gavel requirement from 8.0.5 to 8.1.1

Updates the requirements on [gavel](https://github.com/apiaryio/gavel.js) to permit the latest version.
- [Release notes](https://github.com/apiaryio/gavel.js/releases)
- [Commits](apiaryio/gavel.js@v8.0.5...v8.1.1)

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

package.json

@@ -42,7 +42,7 @@
     "clone": "2.1.2",
     "cross-spawn": "7.0.0",
     "dredd-transactions": "9.0.6",
-    "gavel": "8.0.5",
+    "gavel": "8.1.1",
     "glob": "7.1.4",
     "html": "1.0.0",
     "htmlencode": "0.0.4",