Prevent cosmetic issue where component versions are sometimes labeled as commit hashes

[PromoFaux]

What does this PR aim to accomplish?:

Occasionally core and web master branches can have additional commits ahead of the latest tagged commit - not often, but often enough to make me kick myself when I tag this repo.

This copies the behaviour of bare metal, where the local repository is hard reset to the latest tag.

---

By submitting this pull request, I confirm the following:

1. I have read and understood the contributors guide, as well as this entire template. I understand which branch to base my commits and Pull Requests against.
2. I have commented my proposed changes within the code and I have tested my changes.
3. I am willing to help maintain this change if there are issues with it later.
4. It is compatible with the EUPL 1.2 license
5. I have squashed any insignificant commits. (git rebase)

---

• I have read the above and my PR is ready for review. Check this box to confirm

[yubiuser]

This will increase the image size as we don't need a clone depth 5 in most cases. I think the better approach would be to first check for the branch name and if it's master only clone latest tag; in all other cases only clone depth 1

[PromoFaux]

Indeed, by just over 1mb. I can live with that :)

Edit: also, I tried that approach first, but it doesn't work unfortunately. Cloning a specific tag rather than the branch means the repo ends up in a headless state and then the version script does not work.

It's also not possible to change the depth after it has been cloned - which was another approach I looked at.

In the end, I realised i was starting to add a lot of code just to save 1MB

[yubiuser]

Cloning a specific tag rather than the branch means the repo ends up in a headless state and then the version script does not work.

The trick is to checkout a fake 'master' branch

#1869