pterm slog logger doesn't support anything lower than debug

[nixomose]

I have a logger that runs at trace level and it will never log in pterm, because enabled always returns false because there's no trace level switch case.

https://github.com/pterm/pterm/blob/master/slog_handler.go#L16

[MarvinJWendt]

Hi, currently, PTerm only supports the out-of-the-box slog levels. We are tracking progress here, to make PTerm handle any level: #603