Use build metadata instead of pre-release version for DefaultVersionString

[tminusplus]

What was changed

Uses build metadata instead of a pre-release version for our DefaultVersionString.

Why?

Pre-release versions are parsed as less than a version without pre-release - tags in semver.

Checklist

• Checked version string and tried using tcld to verify that the request does not return a version issue:

❯ ./tcld version
{
    "Date": "2023-09-07T19:49:07Z",
    "Commit": "cee87229532d599ede057f074089de979e6c0338-modified",
    "Version": "v0.1.3+no-version-available"
}

❯ ./tcld user get --user-email <some email>
... user details ...