pyproject: split lint and doc dependencies

This allows a subset of dependencies to be installed if needed and
allows sharing requirements with readthedocs.

.github/workflows/build.yml

@@ -20,19 +20,11 @@ on:
 jobs:
   build:
 
-    runs-on: ubuntu-20.04
-    strategy:
-      matrix:
-        python-version: [3.8, 3.9]
-
+    runs-on: ubuntu-22.04
     steps:
     - uses: actions/checkout@v3
       with:
         submodules: recursive
-    - name: Set up Python ${{ matrix.python-version }}
-      uses: actions/setup-python@v1
-      with:
-        python-version: ${{ matrix.python-version }}
     - name: Install dependencies
       run: |
         pip install poetry

.readthedocs.yml

@@ -0,0 +1,26 @@
+# .readthedocs.yaml
+# Read the Docs configuration file
+# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
+
+# Required
+version: 2
+
+build:
+  os: "ubuntu-22.04"
+  tools:
+    python: "3.10"
+  jobs:
+    post_create_environment:
+      - pip install poetry
+      - poetry config virtualenvs.create false
+    post_install:
+      - poetry install --only=doc
+
+# Build documentation in the doc/main/ directory with Sphinx
+sphinx:
+  configuration: doc/main/conf.py
+  fail_on_warning: true
+
+# Optionally build your docs in additional formats such as PDF
+formats:
+   - pdf