protoc-gen-dubbo-java in osx is missing

[qingyu31]

• have searched the issues of this repository and believe that this is not reolved.
• duplicate with https://github.com/apache/dubbo/issues/5404, however it is closed without fixed.

Environment

• Dubbo version: never mind
• Operating System version: osx
• Java version: 1.8

Steps to reproduce this issue

work with https://dubbo.apache.org/zh/blog/2019/10/28/dubbo-%E5%9C%A8%E8%B7%A8%E8%AF%AD%E8%A8%80%E5%92%8C%E5%8D%8F%E8%AE%AE%E7%A9%BF%E9%80%8F%E6%80%A7%E6%96%B9%E5%90%91%E4%B8%8A%E7%9A%84%E6%8E%A2%E7%B4%A2%E6%94%AF%E6%8C%81-http/2-grpc-%E5%92%8C-protobuf/#%E7%A4%BA%E4%BE%8B-2-%E4%BD%BF%E7%94%A8-protobuf-%E5%BC%80%E5%8F%91-dubbo-%E6%9C%8D%E5%8A%A1

Expected Behavior

generate java files

Actual Behavior

[WARNING] Missing POM for org.apache.dubbo:protoc-gen-dubbo-java:exe:osx-x86_64:1.19.0-SNAPSHOT

protoc-gen-dubbo in osx is never released.

please check with https://repository.apache.org/content/groups/snapshots/org/apache/dubbo/protoc-gen-dubbo-java/1.19.0-SNAPSHOT/