Bump the required osbuild version to v93 (due to the systemd units
change).
Pin the new osbuild version in Schutzfile.
Update repo snapshots in Schutzfile due to osbuild v93 depending on
new selinux-policy build.
RHEL requires the source code for dependencies to be included in the
srpm. The spec file already expects that, but we've only included the
vendored modules (i.e., the `vendor` directory) in the `rhel-8.2.`
branch. Move vendoring to master, so that we can build RHEL packages
from it as well.
This commit is the result of running `go mod vendor`, which includes the
vendored sources and updates go.mod and go.sum files.
Fedora requires the opposite: dependencies should not be vendored. The
spec file already ignores the `vendor` directory by default.
