Bump laravolt/avatar from 1.8.1 to 2.1.0

Bumps [laravolt/avatar](https://github.com/laravolt/avatar) from 1.8.1 to 2.1.0.
- [Release notes](https://github.com/laravolt/avatar/releases)
- [Changelog](https://github.com/laravolt/avatar/blob/master/CHANGELOG.md)
- [Commits](https://github.com/laravolt/avatar/compare/1.8.1...2.1.0)

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

composer.json

@@ -50,7 +50,7 @@
         "jenssegers/date": "^3.4",
         "laravel/framework": "5.6.*",
         "laravel/tinker": "^1.0",
-        "laravolt/avatar": "^1.8",
+        "laravolt/avatar": "^2.1",
         "mccool/laravel-auto-presenter": "^7.1",
         "nexmo/client": "^1.5",
         "pragmarx/google2fa": "^0.7.1",