vala: updated to 0.56.10

Vala 0.56.10
============
* Various improvements and bug fixes:
  - codegen: Don't emit casts in static field initializers
  - parser: Reset tokens buffer when parsing a new source file
  - vala: Output additional information when accessing unknown member
  - vala: Allow "set" method of an container to return void or bool
  - vala: Correctly handle possible null from SourceFile.get_source_line()

* Bindings:
  - glib-2.0: Update return-type of HashTable.add/insert/replace() and
    GenericSet.add()
  - linux: Add resolution field to Input.AbsInfo
  - libpq: Fix a few binding errors

(adam)