Update grape gem

What does this MR do?

Updates grape gem. Set explicit 204 status on delete endpoints when content returned.

Before versions 0.19.0 and 0.19.1 the default status code for delete endpoints was 200 no matter if the content was returned or not. Then for 2 releases 0.19.0 and 0.19.1, they changed it to 204 which was a mistake I believe. We were unlucky enough to update grape during this time and changed all our v4 api to behave in that way. Later starting from 0.19.2 they fixed the mistake by returning 200 if delete has content and 204 if does not.

In order to keep current v4 API behavior without change I explicitly set 204 in each delete endpoint.

Are there points in the code the reviewer needs to double check?

no

Why was this MR needed?

We need newer version for Rails 5 update

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Tests
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?