debian/tests/create-delete: Fix autopkgtest with git 2.45
Set the repository used in the test as safe. Git 2.45 will not trust it by default.
The test is failing with the error below:
2024-06-13T12:06:08.678481+00:00 autopkgtest-lxd-xukspx git-daemon[7458]: fatal: detected dubious ownership in repository at '/var/lib/ikiwiki-hosting-web/git/foo.example.com.git'