Use gleif_hio 0.6.20rc2 on v1.2.14

[kentbull]

Summary

• replace the upstream hio requirement with gleif_hio==0.6.20rc2
• use the same package in all CI dependency bootstrap paths
• avoid installing both distributions, which provide the same hio import package

Purpose

The reason we need this is that certain TCP connection lifecycle bugs are in-progress for hio on main and will be in-progress for a future v0.6.20 release from the ioflo/hio repo once the proposed v0.6.20 branch is accepted.

The following PRs are merged to GLEIF's hio fork on branch release/v0.6.20 that we need in the upstream:

• backport: preserve Remoter sends after peer write EOF GLEIF-IT/hio#3
  • txCutoff: Needed so that Remoter can provide visibility for TCP response cutoff via Remoter.txCutoff rather than incorrectly overloading the TCP receive Remoter.cutoff var as both receive and response cutoffs. Directant/Reactant should look at txCutoff rather than cutoff as the teardown signal, as mentioned in fix: preserve Remoter sends after peer write EOF ioflo/hio#163 to hio main.
• backport: propagate idle timeout to accepted Remoters GLEIF-IT/hio#2
  • timeout -> tymeout: Needed so that expiry/inactivity timeouts work properly on Remoter and the Directant/Reactant pair. Baesd on fix: propagate idle timeout to accepted Remoters ioflo/hio#164
• backport: discard disconnected accepted sockets for 0.6 GLEIF-IT/hio#1
  • Needed so that disconnected sockets are cleaned up. Based on backport: discard disconnected accepted sockets for 0.6 GLEIF-IT/hio#1

Once these changes are accepted into upstream HIO on both main and a future v0.6.20 release branch then the dependency can switch back from gleif_hio to hio.