vala: upgrade 0.56.1 -> 0.56.2

Changes in 0.56.2 LTS release:

  - codegen: Correctly set array-length for NoAccessorMethods properties [#1316]
  - codegen: Detect usage of static type-parameter in runtime context [#1326]
  - vala: Avoid critical in SourceFile.get_mapped_length() [#1330]
  - codegen: Make sure to initialize static collections
  - codegen: Split reserved identifiers for C and Vala
  - codegen: Check cname of fields and methods against reserved identfiers [#1329]
  - glib2.0: Add abs() to int8/int16/int32/ssize_t [#1328]
  - Add initial wayland-client binding
  - Add geocode-glib-2.0 binding
  - Add rest-1.0 bindings

Signed-off-by: Alexander Kanavin <alex@linutronix.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 21913b73)
Signed-off-by: Steve Sakoman <steve@sakoman.com>