[DX] Remove the composer upgrade as unused to narrow focus back to PHP

[TomasVotruba]

When we added this almost 1,5 year ago, it seems like a good idea - https://getrector.org/blog/2021/01/25/introducing-composer-json-rector-rules One one side, upgrading PHP code and composer goes together.

Yet, as time went by, few design and DX problems revealed themselves:

• the composer.json domain is completelly different than PHP - code styling, conventions and format preserving printing
• the project usually upgrade one package at a time - imagine upgrading Symfony 2.8 and Rector forcing you to jump your composer.json config together, even if you don't want to
• for that reasons, it's not used by any vendor packages in core even after 18 months :)
• the way would be to have a standalone project that focused on composer.json only, if needed

For these reasons, we remove this feature from Rector.

We'll keep focusing on PHP to make PHP upgrades more reliable and fun to use 🙂

[lulco]

For me this is huge step back :( is there a way how can I add it back in my rectors?

[TomasVotruba]

As a contributors of this feature, I understood.

If you need it, you can implement this as your own package/tools that handles the composer.json changes.