change for CI

Author: emmanuelle

packages/python/plotly/tox.ini

@@ -60,6 +60,7 @@ deps=
     retrying==1.3.3
     pytest==3.5.1
     pandas==0.24.2
+    xarray==0.10.9
     backports.tempfile==1.0
     optional: --editable=file:///{toxinidir}/../plotly-geo
     optional: numpy==1.16.5
@@ -73,7 +74,6 @@ deps=
     optional: pyshp==1.2.10
     optional: pillow==5.2.0
     optional: matplotlib==2.2.3
-    optional: xarray==0.10.9
     optional: scikit-image==0.14.4
 
 ; CORE ENVIRONMENTS