MAINT: added .readthedocs.yml

Added a yaml for ReadTheDocs.

.readthedocs.yml

@@ -0,0 +1,25 @@
+# .readthedocs.yml
+# Read the Docs configuration file
+# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
+
+# Required version of readthedocs
+version: 2
+
+# Set the version of Python and other tools you might need
+build:
+  os: ubuntu-22.04
+  tools:
+    python: "3.11"
+
+# Build documentation in the docs/ directory with Sphinx
+sphinx:
+   configuration: docs/conf.py
+
+
+# Declare the Python requirements required to build your docs
+python:
+   install:
+    - method: pip
+      path: .
+      extra_requirements:
+        - doc