Bump dehydrated to v0.7.1

Notably this includes support for asynchronous order finalization, which
was tentatively scheduled to be released in April, however was postponed
indefinitely:
https://community.letsencrypt.org/t/enabling-asynchronous-order-finalization/193522/8

However, for a brief period between 7/13 and 7/14, I saw errors issuing
certifcates looking highly similar to what was initially reported when
Let's Encrypt tried the roll out of asychronous order finalization:
https://community.letsencrypt.org/t/openresty-with-resty-auto-ssl-failing-with-curl-error-3/195924/1

Fixes auto-ssl#289

Makefile

@@ -1,7 +1,7 @@
 ROOT_DIR:=$(shell dirname $(realpath $(lastword $(MAKEFILE_LIST))))
 BUILD_DIR?=$(ROOT_DIR)/build
 
-DEHYDRATED_VERSION:=05eda91a2fbaed1e13c733230238fc68475c535e
+DEHYDRATED_VERSION:=ea841998631561543357f032fa7c06598c34d517
 LUA_RESTY_SHELL_VERSION:=955243d70506c21e7cc29f61d745d1a8a718994f
 SOCKPROC_VERSION:=92aba736027bb5d96e190b71555857ac5bb6b2be