[TASK] Only allow (upper) alpha characters for ccurrency shorthand

Configuration/TCA/tx_sgjobs_domain_model_job.php

@@ -394,7 +394,7 @@ return call_user_func(
 					'label' => 'LLL:EXT:' . $extKey . '/Resources/Private/Language/locallang_db.xlf:' . $table . '.salary_currency',
 					'config' => [
 						'type' => 'input',
-						'eval' => 'upper',
+						'eval' => 'alpha, upper',
 						'max' => 3,
 					],
 				],