(docs) change to readthedocs v2

Author: weikang9009

readthedocs.yaml

@@ -0,0 +1,19 @@
+# Required
+version: 2
+
+# Build documentation in the docs/ directory with Sphinx
+sphinx:
+  configuration: doc/conf.py
+
+# Optionally build your docs in additional formats such as PDF and ePub
+formats: all
+
+python:
+    version: 3.7
+    install:
+        - requirements: requirements.txt
+        - method: pip
+          path: .
+          extra_requirements:
+              - tests
+              - docs