FIX: Install doc dependencies using poetry

Author: thclark

.readthedocs.yaml

@@ -1,5 +1,4 @@
 # Read the Docs configuration file
-# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
 
 # Required
 version: 2
@@ -13,19 +12,13 @@ build:
     # nodejs: "19"
     # rust: "1.64"
     # golang: "1.19"
+  jobs:
+    post_create_environment:
+      - pip install poetry
+      - poetry config virtualenvs.create false
+    post_install:
+      - poetry install
 
 # Build documentation in the "docs/" directory with Sphinx
 sphinx:
   configuration: docs/source/conf.py
-
-# Optionally build your docs in additional formats such as PDF and ePub
-# formats:
-#    - pdf
-#    - epub
-
-# Optional but recommended, declare the Python requirements required
-# to build your documentation
-# See https://docs.readthedocs.io/en/stable/guides/reproducible-builds.html
-python:
-  install:
-    - requirements: docs/requirements.txt