Add template for when no git information is available

[ktbarrett]

It's possible for users to download the library from Github without any git history ("Download ZIP" button). Currently that seems to use the template config assuming it's a release. Instead I was wondering if there could be a config option for when there's no git information available so I could write out the version as 2.1+unknown instead of 2.1 so I don't have users who installed a development version in this way reporting the error as version 2.1 as if it were the released version and not some random other version.

[ktbarrett]

@dolfinus Any opinion on this? I've started working on this, but would rather not put more effort into it if it's not going to be accepted.

[dolfinus]

Hi.

setuptools-scm support git archive command by having a file .git_archival.txt with content like this:

node: $Format:%H$
node-date: $Format:%cI$
describe-name: $Format:%(describe:tags=true)$
ref-names: $Format:%D$

Which can be detected by module and used as a source of information when no .git folder is present.

I'm okay with this kind of solution. It can be a dedicated file or a section within pyproject.toml file.

PRs are welcome, no active contribution from me for this feature, sorry.