Fix build with Node 16
Fix build with Node 16

The overload of node::AtExit that takes only two arguments was removed in
https://github.com/nodejs/node/commit/dfc288e7fdbe888f4e134772de421684247f0bea#diff-4acdf5a5c11188763423b746a9a43917c90546f3b48b9aa6f6eeb60e157ae2a7

neon-bindings/neon,neon-bindings/neon,neon-bindings/neon,neon-bindings/neon