fix: api export uri an rate limites

mygb.sh

@@ -164,7 +164,7 @@ _schedule_group_export() {
 
 _group_export_status() {
   _api GET "groups/${group_url_encoded}/export/download" | jq -r '.message' | grep 404 \
-    || echo finished 
+    || echo finished
 }
 
 _wait_group_finished() {
@@ -172,11 +172,12 @@ _wait_group_finished() {
     echo "Waiting end of export ..."
     sleep ${WAITING_TIME}
   done
+  sleep 60
 }
 
 _download_group_export() {
   export_filename="${backup_dir}/$(date +"%Y%m%d_%H%M")_group_${group/\//-}_export.tar.gz"
-  _api GET "group/${group_url_encoded}/export/download" "-o ${export_filename}"
+  _api GET "groups/${group_url_encoded}/export/download" "-o ${export_filename}"
   echo "The group was exported :"
   ls -l "${export_filename}"
 }