diff --git a/workflow/dumping-workflows.rst b/workflow/dumping-workflows.rst
index 5b087fc405b..d1749603155 100644
--- a/workflow/dumping-workflows.rst
+++ b/workflow/dumping-workflows.rst
@@ -309,6 +309,6 @@ The PlantUML image will look like this:
 
 .. image:: /_images/components/workflow/pull_request_puml_styled.png
 
-.. _`Graphviz`: http://www.graphviz.org
+.. _`Graphviz`: https://www.graphviz.org
 .. _`PlantUML`: https://plantuml.com/
 .. _`PlantUML's color list`: https://plantuml.com/color