Update dependencies on '6.2.1' in qt/qtshadertools

Change-Id: Iebecdb2dc9742e63e1c588e03a3fcc4b0761af7c
Reviewed-by: Qt Submodule Update Bot <qt_submodule_update_bot@qt-project.org>

dependencies.yaml

 dependencies:
   ../qtbase:
-    ref: a5dfbb04a7404eab223151dda160597a7698c704
+    ref: 9fa805f7f8dfe96d561e9ed3170770ad768baf93
     required: true