Properly escape reserved chars in yaml
There is a type tightening in yaml parser v4, which causes one unit test to fail.
[TASK] Escape reserved characters in yaml files
In preparation to update the symfony/yaml dependency to v4,
proper escaping needs to take place.
unsufficient escaping will result in a parse error.
Reviewed-by: Christian Kuhn <email@example.com>
Tested-by: Christian Kuhn <firstname.lastname@example.org>
Tested-by: TYPO3com <email@example.com>
Reviewed-by: Jan Helke <firstname.lastname@example.org>
Tested-by: Jan Helke <email@example.com>