deps: update nghttp2 to 1.38.0

Backport-PR-URL: https://github.com/nodejs/node/pull/29123
PR-URL: https://github.com/nodejs/node/pull/27295


Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Yongsheng Zhang <zyszys98@gmail.com>
Reviewed-By: Masashi Hirano <shisama07@gmail.com>