Upgrade to version 1.0 of the http crate

[jplatte]

Things are slowly updating to v1.0 of the http crate, isahc should too! If this is not already in progress elsewhere, I can offer to take a stab at it! :)

[djc]

Given that the last merged PR dates from Nov 2022, I wouldn't hold my breath...

[sagebind]

Apologies! Yes, eventually I intend to upgrade Isahc to the latest http crate version. Unfortunately due to life events, my free time has been significantly limited for the past year and I have not had the bandwidth to work on Isahc (often including discussing issues). It will likely be several more months before things return to normal for me and I can resume work. Upgrading the http crate will probably be incorporated into the planned Isahc 2.0 release.