Fix readthedocs yml connfig error: Value build not found (#411)

Author: MFSY

.readthedocs.yml

@@ -8,9 +8,12 @@ version: 2
 sphinx:
   fail_on_warning: true
 
-# Optionally set the version of Python and requirements required to build your docs
+build:
+  os: ubuntu-22.04
+  tools:
+    python: "3.8"
+
 python:
-  version: "3.8"
   install:
     - method: pip
       path: .