Merge pull request python3statement#78 from pymc-devs/master

Add PyMC3 to list of participating projects

Author: Carreau

_sections/30-projects.md

@@ -25,6 +25,7 @@ These projects pledge to drop Python 2 support in or before 2020.
 - [![](assets/osbrain.png)osBrain](https://github.com/opensistemas-hub/osbrain)
 - [![](assets/pymeasure.png)PyMeasure](https://github.com/ralph-group/pymeasure)
 - [![](assets/rpy2_logo_64x64.png)rpy2](https://rpy2.bitbucket.io)
+- [![](assets/pymc3.png)PyMC3](https://github.com/pymc-devs/pymc3)
 
 &nbsp; <!--break separating project with image from without -->