Address Sorbet error

[abdulapopoola]

What are you trying to accomplish?

Trying to address this new class of Sorbet errors:

Dependabot::Sorbet::Runtime::InformationalError: Return value: Expected type Dependabot::Nuget::Version, got type NilClass
Caller: /home/dependabot/dependabot-updater/lib/dependabot/updater/group_update_creation.rb:295
Definition: /home/dependabot/nuget/lib/dependabot/nuget/update_checker.rb:41 (Dependabot::Nuget::UpdateChecker#lowest_security_fix_version)
  dependabot-updater/vendor/ruby/3.3.0/gems/sorbet-runtime-0.5.11415/lib/types/configuration.rb:301:in `call_validation_error_handler'
  dependabot-updater/vendor/ruby/3.3.0/gems/sorbet-runtime-0.5.11415/lib/types/private/methods/call_validation.rb:310:in `report_error'
  dependabot-updater/vendor/ruby/3.3.0/gems/sorbet-runtime-0.5.11415/lib/types/private/methods/call_validation_2_7.rb:63:in `block in create_validator_method_fast0'
  dependabot-updater/lib/dependabot/updater/group_update_creation.rb:295:in `all_versions_ignored?'
  dependabot-updater/vendor/ruby/3.3.0/gems/sorbet-runtime-0.5.11415/lib/types/private/methods/call_validation_2_7.rb:1029:in `bind_call'
...
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Anything you want to highlight for special attention from reviewers?

How will you know you've accomplished your goal?

The Sorbet error goes away in Sentry.

Checklist

• I have run the complete test suite to ensure all tests and linters pass.
• I have thoroughly tested my code changes to ensure they work as expected, including adding additional tests for new functionality.
• I have written clear and descriptive commit messages.
• I have provided a detailed description of the changes in the pull request, including the problem it addresses, how it fixes the problem, and any relevant details about the implementation.
• I have ensured that the code is well-documented and easy to understand.