Attempt to resolve RTD build failures

Signed-off-by: Matthew Ballance <matt.ballance@gmail.com>

.readthedocs.yaml

@@ -16,7 +16,7 @@ build:
 
 # Build documentation in the "docs/" directory with Sphinx
 sphinx:
-  configuration: docs/conf.py
+  configuration: doc/source/conf.py
   # You can configure Sphinx to use a different builder, for instance use the dirhtml builder for simpler URLs
   # builder: "dirhtml"
   # Fail on all warnings to avoid broken references