change imports for subplots, solves #45

as suggested by @sbecuwe

Author: wdecoster

methplotlib/utils.py

@@ -8,6 +8,8 @@
 import plotly
 from pathlib import Path
 from itertools import chain
+from plotly import subplots
+from plotly.subplots import make_subplots
 
 
 class Region(object):