Fix matrix variable name
diff --git a/ci/build-matrix b/ci/build-matrix
index dac838d..a2dde5e 100755
--- a/ci/build-matrix
+++ b/ci/build-matrix
@@ -8,8 +8,8 @@
 projects = sorted([r.split("/")[-1] for r in glob.glob("images/openstack/projects/*")])
 
 matrix = {
-    "releases": releases,
-    "projects": projects,
+    "release": releases,
+    "project": projects,
 }
 
 json.dump(