Attempt setting requirements file to null
conda:
file: docs/environment.yml
+# The default for requirements_file is null, but for some reason we get an error with this message if it's not set:
+# "Problem parsing YAML configuration. Invalid "requirements_file": path docs/requirements.txt does not exist"
+requirements_file: null
+
python:
version: 3.5
setup_py_install: true
