propose filename for seller export

3rdparty/nlohmann_json

@@ -0,0 +1 @@
+Subproject commit f1768a540a7b7c5cc30cdcd6be9e9ef91083719b

src/gui/mainwindow.cpp

@@ -476,8 +476,8 @@ void MainWindow::onImportSellerJsonActionTriggered()
 
 void MainWindow::onExportSellerJsonActionTriggered()
 {
-    auto filename = QFileDialog::getSaveFileName(this, "Verkäufer exportieren", QString(),
-                                                 "JSON Dateien (*.json)");
+    auto filename = QFileDialog::getSaveFileName(
+        this, "Verkäufer exportieren", QString("kima2_verkaeufer.json"), "JSON Dateien (*.json)");
 
     if (filename.isEmpty())
         return;