.readthedocs.yml: Fix building generation

readthedocs now needs to configure LTP and build metadata/ first.

Fixes: 1bf344a ("doc: add tests catalog page")
Signed-off-by: Petr Vorel <pvorel@suse.cz>

Author: pevik

.readthedocs.yml

@@ -5,8 +5,18 @@ build:
   tools:
     python: "3.6"
   apt_packages:
+    - autoconf
     - enchant-2
     - hunspell-en-us
+    - make
+    - python3-sphinx
+  commands:
+    - make autotools
+    - ./configure
+    - python3 -m virtualenv .venv
+    - . .venv/bin/activate
+    - pip install -r doc/requirements.txt
+    - make -C doc/
 
 # Build from the doc/ directory with Sphinx
 sphinx: