Update to 0.62.2

Summarized Changelog:

• app
  • Fix background image drawing
  • Fix search next/prev button sensitivity
• lib
  • Add missing nullable annotation to spawn child setup functions
  • Fix unused variable warning when not using getrlimit
  • desc is not a smart pointer in 0.62
• widget
  • Fix idle child-exited signal after dispose
  • Limit select-all to the writable region not including the scrollback