Update sphinx config (#250)

Albrja/mic-5802/spinx-config

Fix spinx configuartion
- *Category*: doc build
- *JIRA issue*: https://jira.ihme.washington.edu/browse/MIC-5802

Changes and notes
-sphinx config

### Testing
<!--
Details on how code was verified, any unit tests local for the
repo, regression testing, etc. At a minimum, this should include an
integration test for a framework change. Consider: plots, images,
(small) csv file.
-->

.readthedocs.yml

@@ -1,6 +1,10 @@
 # This is the version for the readthedocs configuration. Version 2 ignores
 # web-based configuration and uses everything from this file.
 version: 2
+# Doc builds will fail if there are any warnings
+sphinx:
+  configuration: docs/source/conf.py
+  fail_on_warning: true
 
 # Configure the python version and environment construction run before
 # docs are built.
@@ -15,7 +19,3 @@ python:
       path: .
       extra_requirements:
         - docs
-
-# Doc builds will fail if there are any warnings
-sphinx:
-  fail_on_warning: true