Modify shell env to bash (#12742)

dolphinscheduler-task-plugin/dolphinscheduler-task-api/src/main/java/org/apache/dolphinscheduler/plugin/task/api/ShellCommandExecutor.java

@@ -101,7 +101,7 @@ public class ShellCommandExecutor extends AbstractCommandExecutor {
                 }
             }
         } else {
-            sb.append("#!/bin/sh\n");
+            sb.append("#!/bin/bash\n");
             sb.append("BASEDIR=$(cd `dirname $0`; pwd)\n");
             sb.append("cd $BASEDIR\n");
             if (StringUtils.isNotBlank(taskRequest.getEnvironmentConfig())) {