fix: `tech-dep` could be mis-read and generate unwanted dependency loops

Signed-off-by: Valentin Lab <valentin.lab@kalysto.org>

bin/compose-core

@@ -2424,6 +2424,7 @@ get_all_relations () {
                     service_list=()
                     array_read-0 service_list < <(array_keys_to_stdin services)
                     providers=()
+                    providers_def=()
                     array_read-0 providers providers_def < <(_get_services_providing "$relation_name" "${service_list[@]}")
                     if [ "${#providers[@]}" == 1 ]; then
                         ts="${providers[0]}"