Update voxpupuli-acceptance requirement from ~> 1.2 to ~> 2.1

Updates the requirements on [voxpupuli-acceptance](https://github.com/voxpupuli/voxpupuli-acceptance) to permit the latest version.
- [Changelog](https://github.com/voxpupuli/voxpupuli-acceptance/blob/master/CHANGELOG.md)
- [Commits](voxpupuli/voxpupuli-acceptance@1.2.0...2.1.0)

---
updated-dependencies:
- dependency-name: voxpupuli-acceptance
  dependency-type: direct:production
...

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

Gemfile

@@ -7,5 +7,5 @@ gem 'onceover-octocatalog-diff',     '~> 0.1', '>= 0.1.8'
 gem 'onceover',                      '~> 3.20'
 gem 'r10k',                          '~> 3.15'
 gem 'ra10ke',                        '~> 2.0'
-gem 'voxpupuli-acceptance',          '~> 1.2'
+gem 'voxpupuli-acceptance',          '~> 2.1'
 gem 'voxpupuli-test',                '~> 6.0'