GdkPixbuf 2.42.8

Changes since 2.42.6
--------------------

- Clear the pixbuf's memory buffer to avoid returning uninitialized memory [#199]
- Turn GdkPixbufModule functions into typed callbacks [!123]
- tiff: Use non-deprecated C99 integer types [!124]
- gif: Check for overflow when compositing or clearing frames [#190]
- Change png/jpeg/tiff build options from boolean to feature [!118]
- jpeg: Do not rely on UB around setjmp/longjmp [#143]
- Build fixes [!114, #185, #182]
- Documentation fixes [!120, !125]
- Translation updates