Support AWS Session tokens for EC2 hosts

Changelog for 0.8.8:

• PR #105 Accommodate Session Tokens for ec2 by @rgee0

Commits
105bf39 Accommodate Session Tokens for ec2 by @rgee0
e5a942d Update to build with Go 1.16 in CI by @alexellis
72d5783 Move to v0.5.0 of cloud-provision by @alexellis

Generated by Derek