Assertion failure crash in `gix_date::time::write::<impl gix_date::Time>::write_to` about gitoxide

[Byron]

It turned out that the --700 date in question could already be parsed losslessly, but additional tests were added to assure correct behaviour around large offset values.

I hope this fixes these date-related issues for good.

[bradlarsen]

I looked back at my old reported issues on gitoxide, and this same problematic input triggered another long-fixed bug in gix! See #950.

[Byron]

Thanks a lot for reporting!

I prefer the GitHub way of presenting the date, as it seems to ignore the invalid offset but presents the unix timestamp that it could parse as UTC. I will add a few tests to see what currently happens, and make sure there is no panic anymore.