Use real release date for "time" value #122

Summary

Hi, it looks like the "time" field in package JSON is the same across all versions of a plugin at the moment and not directly tied to the actual release date of the version. If Composer does add a minimum release age (cooldown) feature (composer/composer#12633) in near future, I assume this is what would be used for that to function? I realize this is just a possibility, but wanted to mention it in case it may be simple to add.

Additional context

No response