Update docs generation

Author: prusse-martin

.readthedocs.yml

@@ -3,15 +3,13 @@ version: 2
 build:
   image: latest
 
-sphinx:
-  configuration: docs/conf.py
-  fail_on_warning: true
-
 python:
-   version: 3.6
-   install:
-      - method: pip
-        path: .
+    version: 3.7
+    install:
+        -   method: pip
+            path: .
+        -   requirements: docs/requirements.txt
 
-conda:
-  environment: base_environment.yml
+sphinx:
+    configuration: docs/conf.py
+    fail_on_warning: true