Dependency updates: png (lovell#320)

Author: github-actions[bot]

versions.properties

@@ -17,7 +17,7 @@ VERSION_LCMS=2.18
 VERSION_MOZJPEG=0826579
 VERSION_PANGO=1.57.0
 VERSION_PIXMAN=0.46.4
-VERSION_PNG=1.6.54
+VERSION_PNG=1.6.55
 VERSION_PROXY_LIBINTL=0.5
 VERSION_RSVG=2.61.91
 VERSION_TIFF=4.7.1