Merge pull request #3508 from jupyterhub/dependabot/pip/ruamel-yaml-clib-0.2.15

Bump ruamel-yaml-clib from 0.2.14 to 0.2.15

Author: manics

requirements.txt

@@ -78,7 +78,7 @@ rsa==4.9.1
     # via google-auth
 ruamel-yaml==0.18.16
     # via chartpress
-ruamel-yaml-clib==0.2.14
+ruamel-yaml-clib==0.2.15
     # via ruamel-yaml
 six==1.17.0
     # via