[v1.4.0] Use go 1.16

This release is moving Fargo to go 1.16 and adds some GitHub actions to automate testing. Fargo dependencies got updated as well.

Expose response HTTP status code in errors

More details in:
#52

Accommodate non-Amazon data center info metadata

See #44

Correct expected status code for deregistration

See #48

Updated op/go-logging

This will update code to support breaking change in op/go-logging repository