Update composer, travis for Symfony4

Author: barryvdh

.travis.yml

@@ -18,15 +18,24 @@ cache:
 env:
   global:
     - setup=basic
+    - symfony="*"
 
 matrix:
   include:
     - php: 5.6
       env: setup=lowest
-    - php: 7.0
-      env: setup=lowest
+        - setup=lowest
+        - symfony="^2.1"
+    - php: 5.6
+        - setup=lowest
+        - symfony="^3"
+    - php: 7.2
+      env:
+        - setup=lowest
+        - symfony="^4"
 
 install:
+  - if [[ $symfony != '*' ]]; then travis_retry composer require symfony/http-foundation:${symfony} --no-update --no-interaction; fi
   - if [[ $setup = 'basic' ]]; then travis_retry composer install --prefer-dist --no-interaction; fi
   - if [[ $setup = 'lowest' ]]; then travis_retry composer update --prefer-dist --no-interaction --prefer-lowest --prefer-stable; fi
 

composer.json

@@ -31,14 +31,14 @@
         "php-http/client-implementation": "^1",
         "php-http/message": "^1.5",
         "php-http/discovery": "^1.2.1",
-        "symfony/http-foundation": "^2.1|^3.0|~4.0",
+        "symfony/http-foundation": "^2.1|^3|^4",
         "moneyphp/money": "^3.0.5"
     },
     "require-dev": {
         "omnipay/tests": "^3",
         "php-http/mock-client": "^1",
-        "squizlabs/php_codesniffer": "^2.8.1",
-        "phpro/grumphp": "^0.11.6"
+        "squizlabs/php_codesniffer": "^3",
+        "phpro/grumphp": "^0.12"
     },
     "extra": {
         "branch-alias": {