[gjs] Created tag 1.57.4

[Philip Chimento <pchimento src gnome org>]

The unsigned tag '1.57.4' was created.

Tagger: Philip Chimento <philip chimento gmail com>
Date: 1563311095 -0700

    Version 1.57.4
    
    - Closed bugs and merge requests:
      * gjs 1.57 requires a recent sysprof version for sysprof-capture-3 [#258,
        !309, Olivier Fourdan]
    
    - Misc documentation changes [Philip Chimento]

Changes since the last tag '1.57.3':

Olivier Fourdan (2):
      build: Remove spurious closing bracket
      build: Add requirement on sysprof 3.33.2

Philip Chimento (4):
      build: Post-release version bump
      Merge branch 'issue258' into 'master'
      Change style guide doc to reflect current best practices
      release: Prepare for 1.57.4