Fix Typo in README

Co-authored-by: Matthias H. <mahartma@mahartma.com>

storage/amazons3/README.md

@@ -19,12 +19,12 @@ Optionally, some configuration parameters may be supplied as GET style parameter
 
 For security reasons, we recommend setting up an S3 bucket and using short-lived credentials such as EC2 instance roles whenever feasible.
 
-In situations where this is not possible, long-lived credentials such as IAM users are a good options.
+In situations where this is not possible, long-lived credentials such as IAM users are a good option.
 
 In both cases, we recommend sticking to the principle of least privilege as outlined in [AWS IAM's best practices][2].
 
 For inspiration, you can have a look at the [AWS Cloudformation template][3] we use to deploy testing infrastructure for this backend.
 
 [1]: https://aws.amazon.com/blogs/aws/amazon-s3-path-deprecation-plan-the-rest-of-the-story/
 [2]: https://docs.aws.amazon.com/IAM/latest/UserGuide/best-practices.html#grant-least-privilege
-[3]: test_setup.template.yaml
+[3]: test_setup.template.yaml