Sidekiq/StoreSecurityScanWorker: TypeError: no implicit conversion of String into Integer

https://sentry.gitlab.net/gitlab/gitlabcom/issues/1612998/?referrer=gitlab_plugin

TypeError: no implicit conversion of String into Integer
  gitlab/ci/parsers/security/scanned_resources.rb:11:in `fetch'
    scanned_resources_sum += report_data.fetch('scan', {}).fetch('scanned_resources', []).length
  gitlab/ci/parsers/security/scanned_resources.rb:11:in `block in scanned_resources_count'
    scanned_resources_sum += report_data.fetch('scan', {}).fetch('scanned_resources', []).length
  gitlab/ci/build/artifacts/adapters/raw_stream.rb:22:in `each_blob'
    yield(stream.read, 'raw') unless stream.eof?
  ci/job_artifact.rb:297:in `block in each_blob'
    file_format_adapter_class.new(stream).each_blob(&blk)
  gitlab_uploader.rb:98:in `open'
    yield(stream)
...
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no implicit conversion of String into Integer