springcloud-jpa-seata sample pom.xml exclude seata issue

`
org.springframework.cloud
spring-cloud-alibaba-seata
0.9.0.RELEASE


io.seata
seata-spring


`
该版本的spring-cloud-alibaba-seata的依赖还是fescar-spring, 所以exclude不起效，再加上后面指定依赖了0.5.0的spring-seata, 导致引入了0.4.2的fescar跟0.5.0的seata, 而又因为包名的改动，生效的却是0.4.2的fescar, 所以即使项目正常启动，GlobalTransactional也是不起作用的。在此把坑指出来，避免大家在上面花过多的时间进行调试。。。望维护团队尽快调整。。。

Locate the springcloud-jpa-seata sample's pom.xml and inspect the spring-cloud-alibaba-seata, seata-spring, and fescar-spring dependencies and exclusions. Compare the resolved dependency versions, then verify that the sample starts with the intended Seata dependency and that GlobalTransactional is effective.

Written by the indexing model from the issue text.