Fix compatibility issue with sulu/[email protected]

[opctim]

Q	A
Bug fix?	no
New feature?	no
BC breaks?	no
Deprecations?	no
Fixed tickets	no
Related issues	346
License	MIT

What's in this PR?

This adds ^3.0 as a version variant for the symfony/event-dispatcher-contracts requirement.

Test

This works as intended with Sulu 2.5.5 while installing locally:

$ composer require "sulu/form-bundle @dev"
Info from https://repo.packagist.org: #StandWithUkraine
./composer.json has been updated
Running composer update sulu/form-bundle
Loading composer repositories with package information
Updating dependencies
Lock file operations: 1 install, 0 updates, 0 removals
  - Locking sulu/form-bundle (2.5.x-dev)
Writing lock file
Installing dependencies from lock file (including require-dev)
Package operations: 1 install, 0 updates, 0 removals
  - Installing sulu/form-bundle (2.5.x-dev): Symlinking from /var/www/stuff/SuluFormBundle
Package sensio/framework-extra-bundle is abandoned, you should avoid using it. Use Symfony instead.
Generating optimized autoload files
composer/package-versions-deprecated: Generating version class...
composer/package-versions-deprecated: ...done generating version class
136 packages you are using are looking for funding.
Use the `composer fund` command to find out more!
phpstan/extension-installer: Extensions installed

Symfony operations: 1 recipe (5d2867546c3cf0471bcc9373207dabc2)
  - Configuring sulu/form-bundle (>=2.4): From github.com/symfony/recipes-contrib:main
Executing script cache:clear [OK]
Executing script assets:install public [OK]
Executing script bin/websiteconsole cache:clear [OK]
Executing script bin/adminconsole sulu:media:init [OK]
Executing script bin/adminconsole massive:search:init [OK]
              
 What's next? 
              

Some files have been created and/or updated to configure your new packages.
Please review, edit and commit them: these files are yours.

 sulu/form-bundle  instructions:

  * The SuluFormBundle is almost ready:
    1. Print the sql statements required to update your database schema by running php bin/console doctrine:schema:update --dump-sql.
    2. If the statements look fine to you, run the same command using --force to execute them.
    3. Make sure your user has all the necessary permissions for the SuluFormBundle.
    4. Use bin/console sulu:form:generate-form to create a dummy form.

  * Read the documentation at https://github.com/sulu/SuluFormBundle/blob/2.x/Resources/doc/index.md

BC Breaks/Deprecations

There are no BCs known.