chore(deps): update external/libexpat digest to ed4090a #39

Job	Run time
lib_android (monero)	25m 36s
lib_android (wownero)	25m 4s
lib_linux (monero)	2m 40s
lib_linux (wownero)	3m 6s
lib_mingw (monero)	3m 31s
lib_sailfishos_aarch64 (monero)	3m 24s
lib_mingw (wownero)	3m 15s
lib_sailfishos_aarch64 (wownero)	3m 1s
lib_darwin (monero)	13m 50s
lib_darwin (wownero)	13m 54s
ios build (monero)	11m 54s
macos build (monero)	3m 10s
ios build (wownero)	13m 42s
lib_sailfishos_i486 (monero)	2m 0s
macos build (wownero)	3m 54s
lib_sailfishos_i486 (wownero)	2m 4s
wallet_cake_android	21m 46s
wallet_xmruw_android (monero)	7m 17s
wallet_xmruw_android (wownero)	6m 43s
comment on pr	7s
	2h 49m 58s

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