Document Gitaly storage breaking change
What does this MR do and why?
With 17.0 Gitaly will no longer allow multiple storages to use the same path. As we previously recommended that admins do this in the docs, we expect this to have some impacts.
Add this to the breaking change document and list a workaround needed if any projects were in a duplicate storage.
MR acceptance checklist
Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.