Changes from 1.2.8:

 • Use Meson as the only build system
 • #773504 - Avoid extra allocations [Garrett Regier]
 • #780550 - meson error looking for python3 [Daniele Forghieri]
 • #769206 - docs: Clarify when NULL might be returned [Matthew Leeds]
 • #766281 - utils/json_from_string: Don't reset user-provided error
             argument [Heinrich Fink]
 • #758580 - json_reader_is_value returns TRUE for null type but
             json_reader_get_value throws an error [Robert Ancell]
 • #768788 - Incorrect account of jsonPath syntax in doc [Allin Cottrell]
 • #774688 - json_from_string() could be optimized to avoid copying the
             root node [Ole André Vadla Ravnås]