bug#57306: guix pull to old commit fails due to unsupported manifest format

[paren--- via Bug reports for GNU Guix]

https://issues.guix.gnu.org/56545#1

> Commit 4ff12d1de7cd617b791996ee7ca1240660b4c20e introduced that bug,
> which was fixed in c9fbd40785a99e13a59d8e530830ce85220a9871:
>
>  https://issues.guix.gnu.org/56441
>
> ‘guix describe’ should show that you’re using a commit in that range.
>
> The solution is to run ‘time-machine’ from a commit outside that range,
> for instance with:
>
>   guix time-machine -- time-machine -C channels.scm -- whatever

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