trying to fix broken readhtedocs build

Author: csparpa

.readthedocs.yml

@@ -0,0 +1,23 @@
+# .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: sphinx/conf.py
+
+# Optionally build your docs in additional formats such as PDF
+formats:
+  - htmlzip
+  - pdf
+
+python:
+  version: 3.7
+  install:
+    - requirements: dev-requirements.txt
+    - requirements: requirements.txt
+    - method: pip
+      path: .

dev-requirements.txt

@@ -2,12 +2,12 @@ coverage
 coveralls
 Jinja2
 pip>=18.0
-pproxy==2.2.0
+pproxy<3
 pytest
 recommonmark
 Sphinx
-sphinx-readable-theme==1.3.0
+sphinx-readable-theme<2
 tox
 tox-travis
 virtualenv
-twine
+twine