Fix row

uebung3/farbenlehre.html

@@ -28,7 +28,7 @@
 
                 function updateTable() {
                         let table = document.getElementById("farben");
-                        table.insertRow(0);
+                        let row = table.insertRow(0);
                         let cell1 = row.insertCell(0);
                         let cell2 = row.insertCell(1);
                         let cell3 = row.insertCell(2);