Release 12.1.4

This release contains a variety of fixes from 12.1.3-1. For information about new features in major release 12, see Release 12.1.0.

A dump/restore is not required for those running 12.1.X.

• Exclude some errors cause transaction level abort.
• Refactor configuration implementaion related to session variables.
• Disable update_process_title when threaded_execution enabled.
• Fix shared_preload_libraries issues and some bugs when threaded_execution enabled.
• Fix issue when logical decoding DELETE operation.
• Fix replication issue when redo COPY FROM operation.
• Remove secondary checkpoint.
• Support setting the default number of undo segments.
• Fix undo allocation issue after vacuum.