Installation failed for PHP 8.0.13 on arch linux

[cdwijs]

Detailed description

I tried to install gitscrum on my arch linux installation, but it doesn't like version 8 of php

Provide a detailed description of the change or addition you are proposing.
$ git clone https://github.com/gitscrum-ce/laravel-gitscrum.git
Cloning into 'laravel-gitscrum'...
remote: Enumerating objects: 8019, done.
remote: Counting objects: 100% (13/13), done.
remote: Compressing objects: 100% (13/13), done.
remote: Total 8019 (delta 5), reused 3 (delta 0), pack-reused 8006
Receiving objects: 100% (8019/8019), 14.08 MiB | 3.37 MiB/s, done.
Resolving deltas: 100% (4266/4266), done.

$ cd laravel-gitscrum/
[cedric@cedric laravel-gitscrum]$ composer update
Loading composer repositories with package information
Updating dependencies
Your requirements could not be resolved to an installable set of packages.

Problem 1
- phpunit/phpunit[6.2.0, ..., 6.5.14] require php ^7.0 -> your php version (8.0.13) does not satisfy that requirement.
- Root composer.json requires phpunit/phpunit ~6.2 -> satisfiable by phpunit/phpunit[6.2.0, ..., 6.5.14].

$ php --version
PHP 8.0.13 (cli) (built: Nov 21 2021 22:49:59) ( NTS )
Copyright (c) The PHP Group
Zend Engine v4.0.13, Copyright (c) Zend Technologies

Make it clear if the issue is a bug, an enhancement or just a question.
This issue is a bug, as the instructions here indicate PHP >=7.1 is supported:
https://github.com/gitscrum-ce/laravel-gitscrum

Context

Why is this change important to you? How would you use it?
This bug prevents me from installing gitscrum on my arch linux system. Therefore I can't use gitscrum until this is fixed.

How can it benefit other users?
Other users are also running arch linux with PHP8, as it's now the standard version on that distribution.

Possible implementation

Not obligatory, but suggest an idea for implementing addition or change.

Your environment

Include as many relevant details about the environment you experienced the bug in and how to reproduce it.
Here's the terminal output:
$ git clone https://github.com/gitscrum-ce/laravel-gitscrum.git
Cloning into 'laravel-gitscrum'...
remote: Enumerating objects: 8019, done.
remote: Counting objects: 100% (13/13), done.
remote: Compressing objects: 100% (13/13), done.
remote: Total 8019 (delta 5), reused 3 (delta 0), pack-reused 8006
Receiving objects: 100% (8019/8019), 14.08 MiB | 3.37 MiB/s, done.
Resolving deltas: 100% (4266/4266), done.

$ cd laravel-gitscrum/
[cedric@cedric laravel-gitscrum]$ composer update
Loading composer repositories with package information
Updating dependencies
Your requirements could not be resolved to an installable set of packages.

Problem 1
- phpunit/phpunit[6.2.0, ..., 6.5.14] require php ^7.0 -> your php version (8.0.13) does not satisfy that requirement.
- Root composer.json requires phpunit/phpunit ~6.2 -> satisfiable by phpunit/phpunit[6.2.0, ..., 6.5.14].

• Version used (e.g. PHP 7.1, HHVM 3):
  $ php --version
  PHP 8.0.13 (cli) (built: Nov 21 2021 22:49:59) ( NTS )
  Copyright (c) The PHP Group
  Zend Engine v4.0.13, Copyright (c) Zend Technologies

• Operating system and version (e.g. Ubuntu 16.04, Windows 7):
  Arch linux
  $ uname -a
  Linux cedric 5.15.7-arch1-1 Instruções de instalação local #1 SMP PREEMPT Wed, 08 Dec 2021 14:33:16 +0000 x86_64 GNU/Linux

• Link to your project: