Update semver requirement from ^5.5.0 to ^6.0.0

Updates the requirements on [semver](https://github.com/npm/node-semver) to permit the latest version.
- [Release notes](https://github.com/npm/node-semver/releases)
- [Changelog](https://github.com/npm/node-semver/blob/master/CHANGELOG.md)
- [Commits](npm/node-semver@v5.5.0...v6.0.0)

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

package.json

@@ -44,7 +44,7 @@
     }
   },
   "dependencies": {
-    "semver": "^5.5.0"
+    "semver": "^6.0.0"
   },
   "devDependencies": {
     "chai": "latest",