[RFC]: Drop ext-openswoole with no replacement

[Xerkus]

Previously, we discussed splitting this package into two each declaring explicit dependency on either ext-swoole or ext-openswoole. A need for such split was dictated by the diverging API in those two extensions.
See https://github.com/laminas/technical-steering-committee/blob/9e73fae14dd1bc8bdcdf875485353269af018de0/meetings/minutes/2023-05-08-TSC-Minutes.md

However, a year and a half passed since that TSC meeting. It is now apparent that openswoole does not have the kind of industry support and project activity required for such a fundamental extension.

At this point, I propose to drop the openswoole support entirely with no replacement. We will immediately remove it from documentation and from composer suggests.

At the same time we will begin a work on the new major release. Starting with a new major release this component will depend on a specific major versions of ext-swoole. This would allow us to utilize latest features in ext-swoole and to handle any BC breaking changes coming from the adoption of the current PHP features or from dependencies like #134

[weierophinney]

I don't think it's entirely apparent that OpenSwoole isn't getting industry support; I actually see an equal number of mentions of both projects, and it's never clear if a mention of "Swoole" is specifically regarding the originating project, or just a generic term used for any Swoole installation, unless there's context pointing either way.

That said, I support this, as it would also be a first step towards creating a separate package specifically for OpenSwoole, which has a diverging API and feature-set.

[Xerkus]

For the signs of the industry support I was specifically looking at the issue activity, PR activity and commit activity in the openswoole repositories.
For the extension last release was a minor release one year ago with the biggest highlight being the php 8.3 support. Next prior release was a major release exactly two years ago.

openswoole pecl page sees around 10k average monthly installs, openswoole/core composer package for the last 30 days had around 20k installs. Usage wise openswoole is not exactly abandoned.
Contributions and maintenance of the extension itself however... are not promising.