changes to the readthedocs build recipe

docs/rtd_environment.yml

 name: rst
 channels:
   - conda-forge
+  - defaults
+channel_priority: strict
 dependencies:
   - cython
   - python=3.7
@@ -12,4 +14,8 @@ dependencies:
   - sphinx
   - sphinx_rtd_theme
   - mock
-  - pillow
\ No newline at end of file
+  - pillow
+  - pip
+  - pip:
+    - recommonmark
+    - readthedocs-sphinx-ext
\ No newline at end of file

environment.yml

 name: rst
 channels:
   - conda-forge
+  - defaults
+channel_priority: strict
 dependencies:
   - cython
   - python=3.7

readthedocs.yml

@@ -10,4 +10,10 @@ sphinx:
   configuration: docs/conf.py
 
 conda:
-  environment: docs/rtd_environment.yml
\ No newline at end of file
+  environment: docs/rtd_environment.yml
+
+python:
+  version: 3.7
+  install:
+    - method: setuptools
+      path: .
\ No newline at end of file