diff --git a/pyproject.toml b/pyproject.toml
index 9da6c99..01cccf1 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -25,6 +25,7 @@ classifiers = [
 
 ]
 dependencies = [
+    "ruamel.yaml ~= 0.18.6",
 ]
 
 [project.urls]