[BUGFIX] Fix deprecated curly braces usage in PHP array

Fixes: #5

Classes/Service/ConfigurationService.php

@@ -103,7 +103,7 @@ class ConfigurationService {
 	protected function getTypoScriptConfiguration() {
 		$configuration = (array) $this->controllerContext->conf;
 		foreach ($configuration as $key => &$option) {
-			if ($key{\strlen($key) - 1} !== '.' && isset($configuration[$key . '.'])) {
+			if ($key[\strlen($key) - 1] !== '.' && isset($configuration[$key . '.'])) {
 				$option = $this->controllerContext->cObj->stdWrap($option, $configuration[$key . '.']);
 			}
 		}