Bump dependency to tomzx/php-semver-checker to ^0.11.

Use the caret instead of the tilde for composer dependencies.
Remove dependency to custom nikic/php-parser.

Author: tomzx

composer.json

@@ -21,29 +21,24 @@
 		"issues": "https://github.com/tomzx/php-semver-checker-git/issues"
 	},
 	"repositories": [
-		{
-			"type": "vcs",
-			"url": "https://github.com/tomzx/php-parser"
-		},
 		{
 			"type": "vcs",
 			"url": "https://github.com/tomzx/gitter"
 		}
 	],
 	"require": {
-		"php": ">=5.4.0",
+		"php": ">=5.5.9",
 
-		"herrera-io/phar-update": "~2.0",
+		"herrera-io/phar-update": "^2.0",
 		"klaussilveira/gitter": "dev-php-semver-checker",
-		"nikic/php-parser": "dev-features/php-semver-checker",
-		"symfony/console": "~2.7|~3.0",
-		"tomzx/finder": "~0.1",
-		"tomzx/php-semver-checker": "~0.10",
-		"vierbergenlars/php-semver": "~3.0"
+		"symfony/console": "^2.7|^3.0",
+		"tomzx/finder": "^0.1",
+		"tomzx/php-semver-checker": "^0.11",
+		"vierbergenlars/php-semver": "^3.0"
 	},
 	"require-dev": {
-		"mockery/mockery": "~0.9",
-		"phpunit/phpunit": "~4.0|~5.0"
+		"mockery/mockery": "^0.9",
+		"phpunit/phpunit": "^4.0|^5.0"
 	},
 	"bin": [
 		"bin/php-semver-checker-git"
@@ -58,6 +53,11 @@
 			"PHPSemVerCheckerGit\\Test\\": "tests/PHPSemVerCheckerGit"
 		}
 	},
+	"config": {
+		"platform": {
+			"php": "5.5.9"
+		}
+	},
 	"extra": {
 		"branch-alias": {
 			"dev-master": "0.6-dev"