deps: add ngtcp2_fmt.c to build configuration (ngtcp2.gyp)

PR-URL: #63821
Reviewed-By: Tim Perry <pimterry@gmail.com>
Reviewed-By: Stephen Belanger <admin@stephenbelanger.com>

Author: ShenHongFei

deps/ngtcp2/ngtcp2.gyp

@@ -17,6 +17,7 @@
       'ngtcp2/lib/ngtcp2_crypto.c',
       'ngtcp2/lib/ngtcp2_dcidtr.c',
       'ngtcp2/lib/ngtcp2_err.c',
+      'ngtcp2/lib/ngtcp2_fmt.c',
       'ngtcp2/lib/ngtcp2_frame_chain.c',
       'ngtcp2/lib/ngtcp2_gaptr.c',
       'ngtcp2/lib/ngtcp2_idtr.c',