Update doc build configuration

Author: vincefn

.readthedocs.yaml

@@ -5,15 +5,11 @@
 # Required
 version: 2
 
-# Set the version of Python and other tools you might need
+# Set the OS, Python version and other tools you might need
 build:
-  os: ubuntu-20.04
+  os: "ubuntu-22.04"
   tools:
-    python: "3.9"
-    # You can also specify other tool versions:
-    # nodejs: "16"
-    # rust: "1.55"
-    # golang: "1.17"
+    python: "mambaforge-latest"
 
 # Build documentation in the docs/ directory with Sphinx
 sphinx:
@@ -23,7 +19,5 @@ sphinx:
 # formats:
 #    - pdf
 
-# Optionally declare the Python requirements required to build your docs
-python:
-   install:
-   - requirements: doc/requirements.txt
+conda:
+    environment: doc/environment.yml

doc/environment.yml

@@ -0,0 +1,12 @@
+name: readthedocs
+channels:
+  - defaults
+  - conda-forge
+dependencies:
+  - sphinx_py3doc_enhanced_theme
+  - docutils=0.20.1    # https://github.com/vidartf/nbsphinx-link/issues/22
+  - m2r2
+  - nbsphinx
+  - nbsphinx-link
+  - numpy
+  - lxml_html_clean