vala: upgrade 0.56.2 -> 0.56.3

vala: upgrade 0.56.2 -> 0.56.3

Changelog:
==========
 * Various improvements and bug fixes:
  - vala: Don't unconditionally expect ObjectType of Class [#1341]
  - vala: Make try-statement parsing more resilient [#1304]
  - vala: Avoid problems with '\' in #line directives on Windows [#1353]
  - gidlparser: Set source reference of parameters

 * Bindings:
  - atspi-2: Fix a few binding errors
  - glib-2.0: Use g_abort for GLib.Process.abort() beginning with 2.50 [#1350]
  - gtk+-3.0: Correctly unhide BindingSet.by_class to avoid Version attribute

Signed-off-by: Wang Mingyu <wangmy@fujitsu.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>