deps: add nghttp3/**/.deps to .gitignore

PR-URL: #51400
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Marco Ippolito <marcoippolito54@gmail.com>

Author: lpinca

deps/ngtcp2/.gitignore

@@ -6,3 +6,4 @@ Makefile
 *gnutls*
 ngtcp2/**/.gitignore
 ngtcp2/**/.deps
+nghttp3/**/.deps