Fix readthedocs.yml format for python install configuration (redis#3529)

Author: petyaslavova

.readthedocs.yml

@@ -2,10 +2,9 @@ version: 2
 
 python:
   install:
+    - requirements: docs/requirements.txt
     - method: pip
       path: .
-    - method: pip
-      requirements: ./docs/requirements.txt
 
 build:
   os: ubuntu-20.04