8.16.0+0.16.0

CHANGES:

• [serapi] (!) support for Coq 8.16, see upstream changes and SerAPI
  test-suite changes for more information. Remarkable
  changes are:
  - kernel terms are serialized a bit differently now due to
  KerName being used in more places upstream. Some
  internal structures also changes in kernel's env, so be
  attentive if you are depending on them.
  - plugin loading is adapted for 8.16 findlib loading
  method
  (@ejgallego)
• [deps] Require cmdliner >= 1.1.0 (@ejgallego)
• [deps] Support Jane Street libraries v0.15.0 (@ejgallego)
• [serapi] New query Objects to dump Coq's libobject (@ejgallego)
• [serlib] Much improved yojson / json support (@ejgallego)
• [serlib] Coq AST now supports ppx_hash intf (ignoring locations by default)
  (@ejgallego)
• [serlib] Coq AST now supports ppx_compare intf (ignoring locations by default)
  (@ejgallego)
• [serlib] Large refactoring on Serlib, using functors, see serlib/README.md
  (@ejgallego)
• [serapi] (!) Query Proofs has changed type and will now return the
  partial terms under construction (#271 , fixes #270, @ejgallego)