replaced import_matplotlib_pyplot with regular plt import to suppor…

…t xarray 2023.9.0

xugrid/plot/plot.py

@@ -4,14 +4,14 @@
 import functools
 
 import numpy as np
+import matplotlib.pyplot as plt
 from xarray.plot.facetgrid import _easy_facetgrid
 from xarray.plot.utils import (
     _add_colorbar,
     _ensure_plottable,
     _process_cmap_cbar_kwargs,
     _update_axes,
     get_axis,
-    import_matplotlib_pyplot,
     label_from_attrs,
 )
 
@@ -251,8 +251,6 @@ def newplotfunc(
             allargs["plotfunc"] = globals()[plotfunc.__name__]
             return _easy_facetgrid(darray, kind="dataarray", **allargs)
 
-        plt = import_matplotlib_pyplot()
-
         # For 3d plot, ensure given ax is a Axes3D object
         if (
             plotfunc.__name__ == "surface"