Default [compat] setting for standard libraries

[sloede]

Julia has started moving standard libraries out of base to make them upgradeable, starting with DelimitedFiles in Julia v1.9 and becoming more prevalent in Julia 1.10 and 1.11 (PSA on Discourse). Correspondingly, #1693 created a new compat entry for the Downloads stdlib.

However, according to the PSA linked above, the recommended way is to set the compat bounds to the same version as the current Julia compat ("1.8"), at least for now. On the other hand, TagBot wants to set the compat bound to just "1". I have already asked in JuliaRegistries/TagBot#292 what the "canonical" way forward is. Until we hear something there (or maybe from somewhere else), I suggest to wait for now before starting to merge these stdlib compat PRs.

[ranocha]

I just followed the recommendation and updated the compat entry to 1.8 in our case - before reading this issue.