Resolve "Plotting CMIP6 data on unstructured grids with psyplot"

Closes #15 (closed)

environment.yml

@@ -3,7 +3,7 @@ name: nbdemo
 channels:
   - conda-forge
 dependencies:
-  - python>=3.7
+  - python=3.7
   - pip
   - ipykernel
   - ipywidgets
@@ -13,7 +13,7 @@ dependencies:
   - netcdf4
   - numpy
   - pandas
-  - matplotlib
+  - matplotlib<3.1
   - cartopy
   - scipy
   - cdo
@@ -30,8 +30,7 @@ dependencies:
   - esmvalcore
   - requests
   - aiohttp
-  - psy-view
-  - psy-reg
+  - psy-maps
   - psyplot
   - pip:
     - envkernel