MAINT: add compatibility with pyface 8.0.0 (#1033)

Co-authored-by: Chengyu Liu <cyliu@aus552cyliu.local>

enable/trait_defs/ui/qt4/rgba_color_editor.py

@@ -29,9 +29,16 @@
 # subclass of the abstract ToolkitEditorFactory class
 # (in traitsui.api) with qt4-specific methods defined.
 # We need to override the implementations of the qt4-specific methods here.
-from traitsui.qt4.color_editor import (
-    ToolkitEditorFactory as BaseColorToolkitEditorFactory,
-)
+
+try:
+    from traitsui.qt.color_editor import (
+        ToolkitEditorFactory as BaseColorToolkitEditorFactory,
+    )
+# compatible with pyface < 8.0.0
+except ModuleNotFoundError:
+    from traitsui.qt4.color_editor import (
+        ToolkitEditorFactory as BaseColorToolkitEditorFactory,
+    )
 
 # -----------------------------------------------------------------------------
 #  The PyQt4 ToolkitEditorFactory class: