Apache Doris made the branch branch-1.2-lts protected. As a result,
all pull requests for this branch should be checked before merging it.
Therefore, we should add a build workflow for this branch.
Features
1. The workflow will trigger the build process if it detects some changes was made for third-party libraries in apache/doris and it will be scheduled every 30 minutes.
2. Release the prebuilts automatically.