Laravel 5.6 updates

Travis config update

Removed HHVM script as Laravel no longer support HHVM after releasing 5.3

vendor/symfony/console/composer.json

@@ -16,16 +16,15 @@
         }
     ],
     "require": {
-        "php": "^5.5.9|>=7.0.8",
-        "symfony/polyfill-mbstring": "~1.0",
-        "symfony/debug": "~2.8|~3.0|~4.0"
+        "php": "^7.1.3",
+        "symfony/polyfill-mbstring": "~1.0"
     },
     "require-dev": {
-        "symfony/config": "~3.3|~4.0",
-        "symfony/event-dispatcher": "~2.8|~3.0|~4.0",
+        "symfony/config": "~3.4|~4.0",
+        "symfony/event-dispatcher": "~3.4|~4.0",
         "symfony/dependency-injection": "~3.4|~4.0",
         "symfony/lock": "~3.4|~4.0",
-        "symfony/process": "~3.3|~4.0",
+        "symfony/process": "~3.4|~4.0",
         "psr/log": "~1.0"
     },
     "suggest": {
@@ -47,7 +46,7 @@
     "minimum-stability": "dev",
     "extra": {
         "branch-alias": {
-            "dev-master": "3.4-dev"
+            "dev-master": "4.1-dev"
         }
     }
 }