Removed python version option from .readthedocs.yaml (#6892)

* added mkdocs config file

* deleted .yml file

* removed python.version from yaml

.readthedocs.yaml

@@ -17,6 +17,5 @@ mkdocs:
 # Optionally declare the Python requirements required to build your docs
 
 python:
-  version: 3.7
   install:
   - requirements: Docs/requirements.txt