minor #44 Fix CI config (tgalopin)

This PR was merged into the main branch.

Discussion
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Fix CI config

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| Tickets       | ...
| License       | MIT

Fix php-cs CI config

Commits
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b820334 Fix CI config

Author: tgalopin

.github/workflows/test.yaml

@@ -11,6 +11,9 @@ jobs:
         runs-on: ubuntu-latest
         steps:
             - uses: actions/checkout@master
+            - uses: shivammathur/setup-php@v2
+              with:
+                  php-version: '7.4'
             - name: php-cs-fixer
               run: |
                   wget https://github.com/FriendsOfPHP/PHP-CS-Fixer/releases/download/v2.16.1/php-cs-fixer.phar -q