Add a MANIFEST.in file

This is solely to workaround setuptool's weird behaviour of not
exercising its default package discovery logic when the setuptools-scm
plugin had to fall back to a static version string during its version
inference.
Due to setuptools-scm order of precedence for git metadata discovery,
this file should only ever be used on a rare occasion, e.g. doing
development builds from a git worktree.

[1] https://setuptools-scm.readthedocs.io/en/latest/usage/#file-finders-hook-makes-most-of-manifestin-unnecessary

Signed-off-by: Erik Skultety <eskultet@redhat.com>

MANIFEST.in

@@ -0,0 +1,7 @@
+# setuptools should no longer need a MANIFEST.in file, but sadly when paired with the
+# setuptools-scm plugin and specifically in a scenario where the fallback_version string needs to
+# be applied setuptools doesn't properly exercise its default package discovery behaviour leading
+# to empty installations, that's where this MANIFEST.in hack comes in and makes sure that our
+# project is properly installed inside the container image environment on this rare occasion.
+
+graft cachi2