Add readthedocs yml file

# .readthedocs.yml

# Read the Docs configuration file

# See https://docs.readthedocs.io/en/stable/config-file/v2.html for details

# Required

version: 2

# Build documentation in the docs/ directory with Sphinx

sphinx:

  configuration: docs/conf.py

# Build documentation with MkDocs

#mkdocs:

#  configuration: mkdocs.yml

# Optionally build your docs in additional formats such as PDF

##formats:

##  - pdf

# Optionally set the version of Python and requirements required to build your docs

python:

  version: 2.7

  install:

    - requirements: requirements.txt

matplotlib<=2.2.4

sympy<=1.4

scipy<=1.2.3

numpy<=1.16.4

h5py'