Loosen versions of dependencies

It has been rather annoying and cumbersome to update these as
new patch versions of gyoku, wasabi, etc are released. My feeling
is that limiting them to the minor version number is fine (because
we might want to verify that a feature exists, for example). This means
that we only need to change this when the minor version changes
Lock Wasabi down to 3.3.0

Seems contradictory, given that I just loosened up the dependencies for
everything else, but the tests are currently failing against Wasabi 3.3.1

Seems that the fixes for Wasabi issue 46 broke operation names. Will need to
revisit that.
Bump HTTPI to v2.3

Gotta get those SSL versions, yo
Bump version to 2.8

Relevant to #639 and #623