[PROPOSAL] Rename OpenSearch.latest.yaml

[dblock]

What/Why

What are you proposing?

Rename OpenSearch.latest.yaml.

What problems are you trying to solve?

The fact that we have two periods in the file name of the API spec (OpenSearch.latest.yaml) is, at the very least, unusual.

What is the developer experience going to be?

Rename the file. Some options:

1. OpenSearch.yml
2. opensearch.yml
3. OpenSearch-API.yml
4. opensearch-api.yml
5. something else?

Are there any breaking changes to the API

Yes, now is the right time to potentially rename this file because we're switching to OpenAPI (#208) and changing the build and release process in #211.

What is the user experience going to be?

A file name that makes more sense.

Are there breaking changes to the User Experience?

The file name will change.

Any remaining open questions?

Is there some kind of naming convention in other products?

[Xtansia]

As far as the OpenAPI specification is concerned, there's no hard rule or standard, just a recommendation here https://spec.openapis.org/oas/v3.1.0#document-structure:

It is RECOMMENDED that the root OpenAPI document be named: openapi.json or openapi.yaml.

[dblock]

There's some chance that we will be including other/separate OpenAPI specs in this repo (e.g. for plugins), so I think we should preserve "OpenSearch" in the name. The core repo is also called OpenSearch, but the spec includes plugins. Maybe we should match the lowercase of the distribution https://artifacts.opensearch.org/releases/bundle/opensearch/2.12.0/opensearch-2.12.0-linux-x64.tar.gz? When we release a versioned spec it should probably be called opensearch-openapi-2.12.0.yaml.

All this said, I think my current preference is opensearch-openapi.yaml.