Fix reference to version that's been removed

Author: Mark-H

VERSION

@@ -0,0 +1 @@
+1.2.0-pl

application.php

@@ -70,9 +70,7 @@
 use modmore\Gitify\Command\UpgradeModxCommand;
 use modmore\Gitify\Gitify;
 
-$composerData = file_get_contents(__DIR__ . "/composer.json");
-$composerData = json_decode($composerData, true);
-$version = $composerData['version'];
+$version = trim(@file_get_contents(__DIR__ . '/VERSION'));
 
 $application = new Gitify('Gitify', $version);
 $application->add(new InitCommand);