docs: build docs from requirements-docs.txt

Signed-off-by: Callahan Kovacs <[email protected]>

.readthedocs.yaml

@@ -16,19 +16,18 @@ build:
     - libapt-pkg-dev
   jobs:
     post_checkout:
+      - git fetch --unshallow || true # See https://docs.readthedocs.io/en/latest/build-customization.html#unshallow-git-clone
       - git fetch --tags --depth 1 # Also fetch tags
       - git describe               # Useful for debugging
 
 # Build documentation in the docs/ directory with Sphinx
 sphinx:
   configuration: docs/conf.py
-  builder: html
+  builder: dirhtml
   fail_on_warning: true
 
 python:
   install:
-    - requirements: docs/requirements.txt
+    - requirements: requirements-docs.txt
     - method: pip
       path: .
-      extra_requirements:
-        - docs

tox.ini

@@ -154,7 +154,7 @@ no_package = true
 env_dir = {work_dir}/docs
 runner = ignore_env_name_mismatch
 deps =
-    -r{tox_root}/docs/requirements.txt
+    -r{tox_root}/requirements-docs.txt
 
 [testenv:build-docs]
 description = Build sphinx documentation