Update readthedocs configuration file (#1382)

Author: erlendvollset

readthedocs.yml

@@ -1,7 +1,18 @@
----
+# Read the Docs configuration file for Sphinx projects
+# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
+
+version: 2
+
 build:
-  image: latest
+  os: ubuntu-22.04
+  tools:
+    python: "3.8"
+
+sphinx:
+  configuration: docs/source/conf.py
+  fail_on_warning: true
 
 python:
-  version: 3.8
-  pip_install: true
+    install:
+    - method: pip
+      path: .