[RegressionFix] Slightly different valgrind leak trace in CI env

.valgrind.suppressions

@@ -28,6 +28,26 @@
    ...
 }
 
+# same as above, but as occurs in CI environment
+{
+   rsvg_error_handle_close2
+   Memcheck:Leak
+   match-leak-kinds: definite
+   fun:malloc
+   fun:g_malloc
+   fun:g_slice_alloc
+   fun:g_error_new_valist
+   fun:g_set_error
+   obj:*/librsvg-2.so*
+   obj:*/librsvg-2.so*
+   obj:*/loaders/libpixbufloader-svg.so
+   obj:*/libgdk_pixbuf-2.0.so*
+   fun:gdk_pixbuf_loader_close
+   fun:gdk_pixbuf_get_file_info
+   fun:get_pixbuf_from_file
+   ...
+}
+
 # rsvg_error_writehandler got fixed in
 # - GNOME/librsvg@7b4cc9b
 # (2018-11-12, first tags: v2.45.0, v2.44.9)