Fix config of readthedocs (#1511)

docs/en/.readthedocs.yaml

@@ -3,6 +3,9 @@ version: 2
 formats:
     - epub
 
+sphinx:
+  configuration: docs/en/conf.py
+
 # Set the version of Python and other tools you might need
 build:
   os: ubuntu-22.04

docs/zh_cn/.readthedocs.yaml

@@ -0,0 +1,19 @@
+version: 2
+
+formats:
+    - epub
+
+sphinx:
+  configuration: docs/zh_cn/conf.py
+
+# Set the version of Python and other tools you might need
+build:
+  os: ubuntu-22.04
+  tools:
+    python: "3.10"
+
+python:
+  install:
+    - requirements: requirements/runtime.txt
+    - requirements: requirements/docs.txt
+    - requirements: requirements/docs_extra.txt