Some of the methods in `Allocations()` incorrectly use the `putQuery`
in API calls where `put` is more appropriate since they are not reading
information back. These methods are also not returning request metadata
such as `LastIndex` back to callers, which can be useful to have in some
scenarios.
They also provide poor developer experience as they take an
`*api.Allocation` struct when only the allocation ID is necessary. This
can lead consumers to make unnecessary API calls to fetch the full
allocation.
Fixing these problems require updating the methods' signatures so they
take `*WriteOptions` instead of `*QueryOptions` and return `*WriteMeta`,
but this is a breaking change that requires advanced notice to consumers.
This commit adds a future breaking change notice and also fixes the
`Stop` method so it properly returns request metadata in a backwards
compatible way.
Luiz Aoqui