Define and document standard filename and location for feature manifest files in SDK repositories

[QuintinWillison]

This will be a quick enough thing to decide on and document, however should be presented to the wider team for consideration before concluding the conformed naming.

For context, see Future Direction for the SDK Manifests.

┆Issue is synchronized with this Jira Uncategorised by Unito

[QuintinWillison]

Making a comment as a trigger in order to attempt to get our Github to Jira sync tool to bring this issue into Jira. Sorry for the noise.

[QuintinWillison]

Thanks, @deanna-lad. The lack of sync was my fault, for having not added the sdk label. Sorry for the noise.

[QuintinWillison]

We've settled on .ably/capabilities.yaml.

See this internal Slack thread for full context, where it was this comment from @lawrence-forooghian that introduced the excellent idea of having an intermediary .ably folder:

We could also take the GitHub approach and have a .ably-tooling (naming up for debate) directory at the root of the repo – I’ve already been thinking about other manifest-like files that I’d like to put in a repo (for providing extra metadata for test observability, for example). Just a thought.

(we dropped the -tooling suffix)

And it was this comment @Rosalita that moved us from 'manifest' to 'capabilities' in respect of the file name, which is much more friendly 😁:

I have no strong opinions on this, but wanted to ask the question, as this is an internal tool should the name contain the word ably e.g. ably-features-manifest.yaml or ably-capabilities.yaml the thinking here is to distinguish it as a file for an internal tool, rather than a file that runs CI or something similar.

Work that now remains to be done under this issue is to document this, probably within the root readme of our new ably/features repository (see ably/ably-common#70 (comment)).