Bump ruamel-yaml from 0.16.10 to 0.16.12

Bumps [ruamel-yaml](https://sourceforge.net/p/ruamel-yaml/code/ci/default/tree) from 0.16.10 to 0.16.12.

Signed-off-by: dependabot-preview[bot] <support@dependabot.com>

requirements.txt

@@ -6,7 +6,7 @@ jsonschema==3.2.0
 kinto-http==10.7.0
 pyrsistent==0.16.0
 requests==2.25.1
-ruamel.yaml==0.16.10
+ruamel.yaml==0.16.12
 six==1.14.0
 Unidecode==1.1.2
 urllib3==1.25.9