container image not buildable from sources

[eskultety]

This has been an issue since pretty much forever when we added setuptools-scm as a dynamic version inference tool in commit a253654. If one tries to actually build the container image from the source tarball, they'll get:

$ tar -xf <ourtarball>.tar.gz && cd <ourtarball>
$ podman build .
[1/7] STEP 1/1: FROM registry.access.redhat.com/ubi9/ubi@sha256:53d6c19d664f4f418ce5c823d3a33dbb562a2550ea249cf07ef10aa063ace38f AS ubi
--> 4d9d35858951
...
File "/tmp/pip-build-env-y2q5mfj8/overlay/lib/python3.9/site-packages/setuptools_scm/_get_version_impl.py", line 117, in _version_missing
          raise LookupError(
      LookupError: setuptools-scm was unable to detect version for /src.

This is because setuptools-scm expects the .git directory to be present in the container build environment which it is not, because .git naturally isn't (and shouldn't be) part of the source tarball.