Merge pull request python3statement#56 from jduckles/swcarpentry

Add Software Carpentry

Author: takluyver

_sections/30-projects.md

@@ -23,6 +23,7 @@ These projects pledge to drop Python 2 support in or before 2020.
 - [![](assets/axelrod.png)Axelrod](https://github.com/Axelrod-Python/Axelrod)
 - [![](assets/osbrain.png)osBrain](https://github.com/opensistemas-hub/osbrain)
 - [![](assets/pymeasure.png)PyMeasure](https://github.com/ralph-group/pymeasure)
+- [![](assets/swcarpentry.png)Software Carpentry](https://software-carpentry.org)
 
 &nbsp; <!--break separating project with image from without -->