Inter limit fix

fixed (one-off) error with limit higher than 2 (solving #388 (closed))

saqc/lib/ts_operators.py

@@ -374,7 +374,7 @@ def interpolateNANs(
             **{
                 "order": order,
                 "method": method,
-                "downgrade_inerpolation": downgrade_interpolation,
+                "downgrade_interpolation": downgrade_interpolation,
             },
         )
     # finally reinsert the dropped data gaps