chore: use mainline libetpan again

now that they merged the fix for downloading cyrus-sasl

.gitmodules

@@ -3,4 +3,4 @@
 	url = git@github.com:deltachat/deltachat-core.git
 [submodule "deltachat-ios/libraries/libetpan"]
 	path = deltachat-ios/libraries/libetpan
-	url = git@github.com:dignifiedquire/libetpan.git
+	url = git@github.com:dinhviethoa/libetpan.git

deltachat-ios/libraries/libetpan

@@ -1 +1 @@
-Subproject commit 6e2a5f9d965fc5b8236c958440ad7ece96c29f90
+Subproject commit a8ed52a7df4fc3e2c5a52237c59a2efaa5857cac