chore(deps): update external/libexpat digest to 8c1d437 #74

Job	Run time
lib_android (monero)	26m 42s
ios build (monero)	11m 18s
lib_darwin (monero)	13m 55s
ios build (wownero)	10m 24s
lib_darwin (wownero)	14m 0s
lib_android (wownero)	25m 21s
lib_linux (monero)	2m 41s
macos build (monero)	3m 40s
lib_linux (wownero)	2m 51s
lib_mingw (monero)	3m 14s
macos build (wownero)	3m 28s
lib_mingw (wownero)	3m 10s
lib_sailfishos_i486 (monero)	2m 35s
lib_sailfishos_aarch64 (monero)	4m 1s
lib_sailfishos_i486 (wownero)	2m 4s
lib_sailfishos_aarch64 (wownero)	4m 5s
wallet_xmruw_android (monero)	6m 41s
wallet_cake_android	20m 6s
wallet_xmruw_android (wownero)	6m 48s
comment on pr	4s
	2h 47m 8s

Provide feedback