analytics: fix type error

[iMichka]

Fixes:
Error: Parameter 'days': Expected type String, got type Integer with value 30 Caller: /opt/homebrew/Library/Homebrew/utils/analytics.rb:273 Definition: /opt/homebrew/Library/Homebrew/utils/analytics.rb:412 (Utils::Analytics.table_output)

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[MikeMcQuaid]

Thanks @iMichka!