Add readthedocs yaml config

Required by readthedocs now, docs build is failing.

Author: glepretre

.readthedocs.yaml

@@ -0,0 +1,15 @@
+# Read the Docs configuration file for Sphinx projects
+# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
+
+version: 2
+
+sphinx:
+  configuration: docs/conf.py
+
+python:
+  install:
+    - method: pip
+      path: .
+      extra_requirements:
+        - docs
+    - requirements: docs/requirements.txt