Adding .readthedocs.yaml to fix RTD build

.readthedocs.yaml

@@ -0,0 +1,19 @@
+# Configuration file for ReadTheDocs, used to render CV-X-IF documentation.
+# Copyright 2023 OpenHW Group
+# SPDX-License-Identifier:Apache-2.0 WITH SHL-2.1
+
+version: 2
+
+build:
+  os: "ubuntu-20.04"
+  tools:
+    python: "3.9"
+
+# Build from the docs/source directory with Sphinx
+sphinx:
+  configuration: docs/source/conf.py
+
+# Explicitly set the Python requirements
+python:
+  install:
+    - requirements: docs/requirements.txt