diff --git a/scripts/extract_dockerfile_matrix.py b/scripts/extract_dockerfile_matrix.py
index 9557d3d..1cd0b5d 100755
--- a/scripts/extract_dockerfile_matrix.py
+++ b/scripts/extract_dockerfile_matrix.py
@@ -15,7 +15,7 @@
 
 if isinstance(buildspec.get("source"), str):
     out.append({
-        "key": 0,
+        "key": 1,
         "file": buildspec["source"],
         "common": False
     })
@@ -37,4 +37,4 @@
         idx += 1
 
 
-print(json.dumps(out))
\ No newline at end of file
+print(json.dumps(out))