Don't ignore .git folder in docker build

[lovromazgon]

Description

This makes sure our docker build includes the .git folder, which should give us access to the git tag and let us build the version string 🤞

Fixes (hopefully) #895

[maha-hajja]

let's hope it works 🤞🏼

[hariso]

IIRC, it was removed to reduce Docker build time. WDYT about getting the version from git and saving it to a file, then sending it to Docker?

[lovromazgon]

I just tried it out to see what difference it makes, I ran docker build -f Dockerfile -t conduit-local . and then removed the image two times in a row (second run caches almost everything except loading the context). I ran it on main and on this branch, here are the results:

• main first run 79.8s, second run 5.0s
• lovro/dockerignore first run 74.4s, second run 6.3s

I wouldn't say that's a noticeable difference and I don't think we should optimize this further if it solves the problem, it's just not worth it. Especially because our docker builds are triggered nightly and on releases, a few seconds don't make a difference there.

[hariso]

Definitely, just one second of difference is not worth it.