[MINOR] Add support for symfony 5

.travis.yml

@@ -44,6 +44,15 @@ matrix:
     - stage: test
       php: 7.4
       env: SYMFONY_VERSION=4.2.*
+    - stage: test
+      php: 7.3
+      env: SYMFONY_VERSION=4.3.*
+    - stage: test
+      php: 7.3
+      env: SYMFONY_VERSION=4.4.*
+    - stage: test
+      php: 7.3
+      env: SYMFONY_VERSION=5.0.*
   allow_failures:
     - php: 7.4
       env: TARGET=checkdeps

composer.json

@@ -31,15 +31,15 @@
         "psr/http-message": "^1.0",
         "sonata-project/block-bundle": "^3.18",
         "sonata-project/core-bundle": "^3.17",
-        "symfony/config": "^4.2",
-        "symfony/dependency-injection": "^4.2",
-        "symfony/expression-language": "^4.2",
-        "symfony/form": "^4.2",
-        "symfony/framework-bundle": "^4.2",
-        "symfony/http-foundation": "^4.2",
-        "symfony/http-kernel": "^4.2",
-        "symfony/options-resolver": "^4.2",
-        "symfony/twig-bundle": "^4.2"
+        "symfony/config": "^4.2 || ^5.0",
+        "symfony/dependency-injection": "^4.2 || ^5.0",
+        "symfony/expression-language": "^4.2 || ^5.0",
+        "symfony/form": "^4.2 || ^5.0",
+        "symfony/framework-bundle": "^4.2 || ^5.0",
+        "symfony/http-foundation": "^4.2 || ^5.0",
+        "symfony/http-kernel": "^4.2 || ^5.0",
+        "symfony/options-resolver": "^4.2 || ^5.0",
+        "symfony/twig-bundle": "^4.2 || ^5.0"
     },
     "require-dev": {
         "bamarni/composer-bin-plugin": "^1.3",