Support for psalm/phar installation

[rela589n]

Hello!

First of all, thanks for maintaining such a beautiful tool that helps developers to write a better software. I think most of PHP open-source world has substantially benefited from using Psalm.

I'm wondering why isn't it possible to use psalm/plugin-phpunit along with psalm/phar installation?

After installing "psalm/phar": "^5.25" in composer.json file and then trying to composer req --dev psalm/plugin-phpunit I get the following error:

Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - psalm/plugin-phpunit 0.19.0 requires vimeo/psalm dev-master || ^5@beta || ^5.0 -> satisfiable by vimeo/psalm[5.0.0, ..., 5.25.0].
    - psalm/plugin-phpunit 0.18.4 requires vimeo/psalm dev-master || dev-4.x || ^4.7.1 || ^5@beta || ^5.0 -> satisfiable by vimeo/psalm[4.7.1, ..., 4.30.0, 5.0.0, ..., 5.25.0].
    - psalm/plugin-phpunit[0.18.0, ..., 0.18.3] require vimeo/psalm dev-master || dev-4.x || ^4.5 || ^5@beta -> satisfiable by vimeo/psalm[4.5.0, ..., 4.30.0, 5.0.0, ..., 5.25.0].
    - psalm/plugin-phpunit[0.16.0, ..., 0.17.0] require vimeo/psalm dev-master || dev-4.x || ^4.5 -> satisfiable by vimeo/psalm[4.5.0, ..., 4.30.0].
    - psalm/plugin-phpunit[0.14.0, ..., 0.15.2] require vimeo/psalm dev-master || dev-4.x || ^4.0 -> satisfiable by vimeo/psalm[4.0.0, ..., 4.30.0].
    - psalm/phar 5.25.0 conflicts with vimeo/psalm 5.25.0.
    - psalm/phar 5.25.0 conflicts with vimeo/psalm 5.24.0.
    - psalm/phar 5.25.0 conflicts with vimeo/psalm 5.23.1.
    - psalm/phar 5.25.0 conflicts with vimeo/psalm 5.23.0.
    - ...

It seems that the only way to use plugin is to require the psalm itself with all it's dependencies. But in my case, I'd like to use amphp/amp^3.0 and it could not be installed along with the Psalm 5.x.

I hope that there would be some way to use the plugins with phar installation