Merge pull request #3487 from jupyterhub/dependabot/pip/ruamel-yaml-0.18.16

Bump ruamel-yaml from 0.18.15 to 0.18.16

Author: manics

requirements.txt

@@ -76,7 +76,7 @@ requests-oauthlib==2.0.0
     # via kubernetes
 rsa==4.9.1
     # via google-auth
-ruamel-yaml==0.18.15
+ruamel-yaml==0.18.16
     # via chartpress
 ruamel-yaml-clib==0.2.14
     # via ruamel-yaml