Version 1.55.2

- Closed bugs and merge requests:
  * Gnome-shell crashes on destroying cached param specs [#213, !240, Marco
    Trevisan]
  * Various maintenance [!235, !250, Philip Chimento]
  * Auto pointers builder [!243, Marco Trevisan]
  * configure.ac: Update bug link [!245, Andrea Azzarone]
  * SIGSEGV when exiting gnome-shell [#212, !247, Andrea Azzarone, Philip
    Chimento]
  * Fix build with --enable-dtrace and create CI job to ensure it doesn't break
    in the future [#196, !237, !253, Philip Chimento]
  * Delay JSString-to-UTF8 conversion [!249, Philip Chimento]
  * Annotate return values [!251, Philip Chimento]
  * Fix a regression with GError toString() [!252, Philip Chimento]
  * GType memleak fixes [!244, Marco Trevisan]
  * Atoms refactor [!233, Philip Chimento, Marco Trevisan]
  * Write a "Code Hospitable" README file [#17, !248, Philip Chimento, Andy
    Holmes, Avi Zajac]
  * object: Method lookup repeatedly traverses introspection [#54, !53, Colin
    Walters, Philip Chimento]
  * Handler of GtkEditable::insert-text signal is not run [#147, !143, Tomasz
    Miąsko, Philip Chimento]