Allow Symfony 5 (#214)

* Allow Symfony 5

* Update .travis.yml

Author: barryvdh

.travis.yml

@@ -30,6 +30,8 @@ matrix:
       env: setup=lowest symfony="^3"
     - php: 7.1
       env: setup=lowest symfony="^4"
+    - php: 7.2
+      env: setup=lowest symfony="^5"
   allow_failures:
     - php: 7.4snapshot
 

composer.json

@@ -42,7 +42,7 @@
         "php-http/client-implementation": "^1",
         "php-http/message": "^1.5",
         "php-http/discovery": "^1.2.1",
-        "symfony/http-foundation": "^2.1||^3||^4",
+        "symfony/http-foundation": "^2.1|^3|^4|^5",
         "moneyphp/money": "^3.1"
     },
     "require-dev": {