Upstream GitHub API BC break broken self-update

[asgrim]

Upstream bug report: ThePHPF/attestation#27

• Pull the latest attestation library update once released
• Handle errors with better messaging to help users in future if this scenario happens again

[asgrim]

Upstream PR ThePHPF/attestation#28 will fix upstream issue

[asgrim]

Note; even with fix #677 implemented, users will have issues using pie self-update unless GH happen to revert the BC break.. unfortunately nothing we can do about that now :(