Enable compiled packages to be used in RTD.

CsatiZoltan · CsatiZoltan · commit 9f1d3f3eaa9a · 2020-09-08T18:58:01.000+02:00
readthedocs/readthedocs.org#1639 (comment) https://github.com/LaurentRDC/scikit-ued/blob/master/.readthedocs.yml
diff --git a/.readthedocs.yaml b/.readthedocs.yaml
@@ -18,4 +18,5 @@ python:
   version: 3.7
   install:
     - requirements: docs/source/requirements.txt
+  system_packages: true
 
