Two tests assumed that `refs/remotes/rad/HEAD` would automatically be
crated. It turns out, however, that this only the case if executed
with Git 2.48.0 or newer. Git versions older than 2.48.0 do not touch
'refs/remotes/<remote>/HEAD'.
Git 2.48.0 and newer will update `refs/remotes/<remote>/HEAD` by
default. This can be disabled by setting
`remote.<remote>.followRemoteHEAD` to "never". Thus, with these
versions, setting that configuration to "never" emulates the behaviour
of older versions.
Therefore, to ensure that test results are consistent across Git
versions before and after 2.48.0, the fixture of test repositories
now include setting 'remote.rad.followRemoteHEAD = never'.
The affected tests are adjusted accordingly.
This change can possibly be reverted once Radicle requires usage of Git
2.48.0 or newer.
Co-authored-by: Lorenz Leutgeb <lorenz.leutgeb@radicle.xyz>