fix readthedocs build (#581)

* Create .readthedocs.yaml

Needed since of late to keep building on rtd
https://docs.readthedocs.io/en/stable/config-file/v2.html

* rtd: fail on warnings

* rtd: requirements.txt

* Trigger Jenkins

---------

Co-authored-by: Peter Putz <peter@absolutecycling.com>

.readthedocs.yaml

@@ -0,0 +1,17 @@
+# Read the Docs configuration file
+# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
+
+version: 2
+
+build:
+  os: ubuntu-22.04
+  tools:
+    python: "3.11"
+
+sphinx:
+  configuration: conf.py
+  fail_on_warning: true
+
+python:
+  install:
+  - requirements: requirements.txt