Months are computed wrongly when using format-locale in a negative offset timezone

[brunolopesr]

Describe the bug
When using the prop format-locale with a browser using a timezone different from UTC (probably timezones with negative offsets like America/Sao_Paulo), the months of a year are computed wrong, from December to November.

To Reproduce
Set your browser timezone to a value different from UTC or +00:00, then use a date-fns locale as a value of the prop format-locale

Codesandbox: https://codesandbox.io/p/devbox/prod-glitter-lm5nsv

Expected behavior
The months should be in the correct order from January to December

Screenshots

Desktop & mobile (please complete the following information):

• Browser: Google Chrome 123.0.6312.105
• Library version: v8.4.0

[brunolopesr]

Made a PR #818 that I think will fix this problem.

I believe it just occurs in negative timezone offsets, because as the ISO 8601 strings used to compute month dates are always something like 2017-01-01T00:00-00:00, it then makes a date one day earlier, that will be the last day of the previous month.

[brunolopesr]

Well, the bug exists in this package for at least 9 months, made the PR above to fix the problem and it was closed because the maintainer has a simpler fix..

As I don't want to wait for this fix, as I dont know if it will be in the next day or the next year, I'm closing the issue.

[Jasenkoo]

WIll keep it open, as it will be fixed in the next release