Can't install composer deps on v3

[Eugene Leonovich]

composer install

No lock file found. Updating dependencies instead of installing from lock file. Use composer update over composer install if you do not have a lock file.
Loading composer repositories with package information
Updating dependencies
Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - psalm/phar[3.11.0, ..., 3.18.2] require php ^7.1 -> your php version (8.0.0) does not satisfy that requirement.
    - Root composer.json requires psalm/phar ^3.11@dev -> satisfiable by psalm/phar[3.11.0, ..., 3.18.2].

Running composer require psalm/phar does the trick (and bumps the package version to 4.3.1), but makes the existing psalm.xml incompatible with the new version:

vendor/bin/psalm.phar

Problem parsing .../develop/try/amp/psalm.xml:
  Could not resolve config path to .../develop/try/amp//lib/CallableMaker.php

Env:

php -v
PHP 8.0.0 (cli) (built: Nov 30 2020 13:47:29) ( NTS )
Copyright (c) The PHP Group
Zend Engine v4.0.0-dev, Copyright (c) Zend Technologies
    with Xdebug v3.0.1, Copyright (c) 2002-2020, by Derick Rethans
    with Zend OPcache v8.0.0, Copyright (c), by Zend Technologies

composer --version
Composer version 2.0.8 2020-12-03 17:20:38

[Niklas Keller]

--ignore-platform-reqs should also help. But it's probably time to upgrade Psalm.