Fix oops in workflows intro

Author: alexstaeding

chapters/workflows/intro.tex

@@ -15,7 +15,7 @@ \section{Git Workflows}\label{sec:git-workflows}
         \draw[parent] (c.west) to (a.east);
         \draw[ref-arc] (master) to (b);
         \draw[ref-arc] (feature) to (c);
-        \draw[parent, double] (feature) to (master){???};
+        \draw[parent, double] (feature) to (master);
     \end{tikzpicture}
 \end{frame}