Restore Orange.canvas.report module stub

The stub module was removed in biolabgh-3772 without a corresponding
'FutureWarning' grace period.

Author: ales-erjavec

Orange/canvas/report.py

@@ -0,0 +1,11 @@
+import sys
+import warnings
+import Orange.widgets.report
+
+warnings.warn(
+    f"'{__name__}' is deprecated and will be removed in the future.\n"
+    "The contents of this package were moved to 'Orange.widgets.report'. "
+    "Please update the imports accordingly.",
+    FutureWarning, stacklevel=2
+)
+sys.modules[__name__] = Orange.widgets.report