Remove the self-update command.

It apparently wasn't working (the manifest file didn't exist) and is based on a deprecated package.

Author: tomzx

composer.json

@@ -20,10 +20,9 @@
 		"issues": "https://github.com/tomzx/php-semver-checker/issues"
 	},
 	"require": {
-		"php": ">=5.5.0",
+		"php": ">=5.5.9",
 
 		"hassankhan/config": "^0.10",
-		"herrera-io/phar-update": "^2.0",
 		"nikic/php-parser": "^3.1",
 		"symfony/console": "^2.7|^3.0",
 		"symfony/yaml": "^2.7|^3.0",

composer.lock

@@ -3,7 +3,6 @@
 namespace PHPSemVerChecker\Console;
 
 use PHPSemVerChecker\Console\Command\CompareCommand;
-use PHPSemVerChecker\Console\Command\SelfUpdateCommand;
 use Symfony\Component\Console\Application as SymfonyApplication;
 
 class Application extends SymfonyApplication {
@@ -31,7 +30,6 @@ protected function getDefaultCommands()
 	{
 		$commands = parent::getDefaultCommands();
 		$commands[] = $this->add(new CompareCommand());
-		$commands[] = $this->add(new SelfUpdateCommand());
 		return $commands;
 	}
 }