Fix composer installation to use PHP 8.3

Author: kornrunner

.github/workflows/run-tests.yml

@@ -30,7 +30,7 @@ jobs:
 
       - name: Install dependencies
         run: |
-          docker run --rm -v $GITHUB_WORKSPACE:/app -w /app composer:2 install --no-interaction --prefer-dist
+          docker run --rm -v $GITHUB_WORKSPACE:/app -w /app php:8.3-cli sh -c "curl -sS https://getcomposer.org/installer | php && php composer.phar install --no-interaction --prefer-dist"
 
       - name: Run tests
         run: |