Re-enable CI-test with flag 'prefer-lowest'

Changes
=======

* Set variable to use correct phpunit to run on lowest
  See symfony/symfony#52844
* Up the minimum-requirement for symfony/flex for demo/sf5.4 to 1.21
* Update minimal version of doctrine/doctrine-bundle to allow installing with prefer-lowest on sf 5.4

.github/workflows/ci.yml

@@ -54,12 +54,13 @@ jobs:
         php-version: ['7.2', '7.3', '7.4', '8.0', '8.1', '8.2']
         composer-options: ['--prefer-stable']
         dependency-versions: ['highest']
-# Disable lowest for now
-#        include:
-#          # testing lowest PHP version with lowest dependencies
-#          - php-version: '7.2.5'
-#            dependency-versions: 'lowest'
-#            composer-options: '--prefer-lowest'
+        include:
+          # testing lowest PHP version with lowest dependencies
+          - php-version: '7.2.5'
+            dependency-versions: 'lowest'
+            composer-options: '--prefer-lowest'
+            env:
+              SYMFONY_PHPUNIT_VERSION: 7
 
     steps:
       - name: "Checkout code"
@@ -83,6 +84,8 @@ jobs:
 
       - name: Unit Tests
         run: vendor/bin/simple-phpunit
+        env:
+          SYMFONY_PHPUNIT_VERSION: "${{ matrix.dependency-versions == 'lowest' && '7' || '' }}"
 
       - name: Install symlinks for demo's
         uses: "ramsey/composer-install@v2"
@@ -100,6 +103,8 @@ jobs:
 
       - name: Demo symfony5.4 - Unit Tests
         run: demo/symfony5.4/bin/phpunit -c demo/symfony5.4/phpunit.xml.dist
+        env:
+          SYMFONY_PHPUNIT_VERSION: "${{ matrix.dependency-versions == 'lowest' && '7' || '' }}"
 
       - name: Demo symfony6.x - Install  dependencies
         uses: "ramsey/composer-install@v2"

composer.json

@@ -8,7 +8,7 @@
 		"php": "^7.2|^8.0",
 		"paragonie/halite": "^4.6|^5.0",
 		"doctrine/orm": "^2.5",
-		"doctrine/doctrine-bundle": "^2.0",
+		"doctrine/doctrine-bundle": "^2.0.8|^2.1",
 		"symfony/property-access": "^5.4|^6.0|^7.0",
 		"symfony/dependency-injection": "^5.4|^6.0|^7.0",
 		"symfony/yaml": "^5.4|^6.0|^7.0",

demo/symfony5.4/composer.json

@@ -12,7 +12,7 @@
         "paragonie/halite": "^4.6|^5.0",
         "symfony/console": "5.4.*",
         "symfony/dotenv": "5.4.*",
-        "symfony/flex": "^1.17|^2",
+        "symfony/flex": "^1.21|^2",
         "symfony/framework-bundle": "5.4.*",
         "symfony/runtime": "5.4.*",
         "symfony/twig-bundle": "5.4.*",