Guard scripts from being run in non-CLI contexts

Author: nicolas-grekas

Resources/bin/yaml-lint

@@ -10,6 +10,10 @@
  * file that was distributed with this source code.
  */
 
+if ('cli' !== \PHP_SAPI) {
+    throw new Exception('This script must be run from the command line.');
+}
+
 /**
  * Runs the Yaml lint command.
  *