Use gitaly 0.97.0

What does this MR do?

We are seeing more and more incidents where gitaly-ruby "gets stuck" and all request that are sent to it fail with gRPC ResourceExhausted, without any description. The only workaround we have at the moment is to manually restart gitaly-ruby.

In Gitaly 0.97.0 we have added health checks so that these restarts should happen automatically. We also increased the log level of the grpc library in gitaly-ruby, in the hopes that we might see some errors in our logs that point to what's going wrong.

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

Why was this MR needed?

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
  • Has been reviewed by Backend
  • Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together
• Internationalization required/considered
• End-to-end tests pass (package-and-qa manual pipeline job)

What are the relevant issue numbers?