composer.json update version constraints to use ^ instead of ~

Author: ek9

composer.json

@@ -26,17 +26,17 @@
     },
     "require": {
         "php": ">=5.6",
-        "phpunit/php-code-coverage": "~5.0",
-        "behat/behat": "~3.0",
-        "guzzlehttp/guzzle": "~6.0",
-        "symfony/config": "~2.3||~3.0||~4.0",
-        "symfony/dependency-injection": "~2.2||~3.0||~4.0",
-        "symfony/expression-language": "~2.2||~3.0||~4.0",
-        "symfony/http-kernel": "~2.3||~3.0||~4.0",
-        "symfony/http-foundation": "~2.3||~3.0||~4.0"
+        "phpunit/php-code-coverage": "^5.0",
+        "behat/behat": "^3.0",
+        "guzzlehttp/guzzle": "^6.0",
+        "symfony/config": "^2.3||^3.0||^4.0",
+        "symfony/dependency-injection": "^2.2||^3.0||^4.0",
+        "symfony/expression-language": "^2.2||^3.0||^4.0",
+        "symfony/http-kernel": "^2.3||^3.0||^4.0",
+        "symfony/http-foundation": "^2.3||^3.0||^4.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "~6.0",
+        "phpunit/phpunit": "^6.0",
         "mikey179/vfsStream": "1.6.*"
     },
     "suggest": {