Fix kwargs warning in microsoft_teams notifier

What does this MR do?

Fix Ruby 2.7 kwarg warnings for Gitlab::Octokit::Middleware when running bundle exec spec ee/spec/models/project_services/github_service_spec.rb:212

Related issue: #257438 (closed)

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• [-] Merge request performance guidelines
• Style guides
• [-] Database guides
• [-] Separation of EE specific content