Content Update Scheduler v1.1

Note: Development has been continued with the help of the pull request from this fork by the Immediate Media Co team and the assistance of aider with Claude 3 Opus to reduce the required effort.

v1.1 Changelog

• Pull request #4 from @immediate-media merged
• Use local WordPress time zone instead of UTC+1
• Retain original post author during republication
• Deduplication of some pieces of code
• Deprecated functions and practices reduced
• Replaced the date_i18n() function with the newer wp_date() function
• Simplified the checkTime function in js/publish-datepicker.js
• Wrapped wp_get_current_user() call in a conditional to check if the user is logged in