Don't crash the build when trying to docker-package from a shallow clone of a commit

[HarHarLinks]

wearing a Nordeck hat - I hope the source branch is sufficient to auth that fact.

Pending clarification how to handle CLA between Nordeck and Element.

Checklist

• Tests written for new code (and old code if feasible).
• New or updated public/exported symbols have accurate TSDoc documentation.
• Linter and other CI checks pass.
• I have licensed the changes to Element by completing the Contributor License Agreement (CLA)

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[t3chguy]

Looks sane

[richvdh]

Hi @HarHarLinks,

Pending clarification how to handle CLA between Nordeck and Element.

Any progress on getting that clarification?

[HarHarLinks]

@neilisfragile is on it