bkernel: also update dnf5 avoid on bkernel01/02

Signed-off-by: Kevin Fenzi <kevin@scrye.com>

roles/bkernel/files/bkernel-site-defaults.cfg

@@ -9,3 +9,9 @@ config_opts['dnf_common_opts'] = ['--setopt=install_weak_deps=0']
 config_opts['environment']['LANG'] = 'C.UTF-8'
 config_opts['use_bootstrap'] = False
 config_opts['dnf_warning'] = False
+
+# dnf group install with '--allowerasing' is still to be released:
+# https://github.com/rpm-software-management/dnf5/pull/1174
+config_opts["dnf5_avoid_opts"] = {
+    "group": ["--allowerasing"],
+}