Remove the 3 lines below if they're there, or comment them out with -- :
At the start:
-- SET @@SESSION.SQL_LOG_BIN= 0;
-- SET @@GLOBAL.GTID_PURGED=/*!80000 '+'*/ '';
At the end:
-- SET @@SESSION.SQL_LOG_BIN = @MYSQLDUMP_TEMP_LOG_BIN;
Note that the comment characters are "dash dash space" including the space.
A better solution is to stop these lines from being written to the dump file at all by including the option --set-gtid-purged=OFF on your mysqldump command.