fix: update dayjs call

[adajoy]

add ".default" to avoid error "dayjs is not a function".

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Other information:

[jbartkowiak]

Hey @adajoy, thanks for fixing this! Just stumbled upon this and began wasting time on it ;-)

[billyyyyy3320]

Thanks for your PR.

I found it's an issue from dayjs and webpack which they have already handled it.

webpack/webpack#4742
iamkun/dayjs#480
iamkun/dayjs#492

[billyyyyy3320]

Closed by #94