Fix the type of the externalAccountRequired field

CHANGELOG.md

@@ -18,6 +18,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 - Wildcard certificates are now supported. In the file name, the `*` is replaced by `_`.
 
+### Fixed
+- In the directory, the `externalAccountRequired` field is now a boolean instead of a string.
+
 ## [0.6.1] - 2019-09-13
 
 ### Fixed

acmed/src/acme_proto/structs/directory.rs

@@ -8,7 +8,7 @@ pub struct DirectoryMeta {
     pub terms_of_service: Option<String>,
     pub website: Option<String>,
     pub caa_identities: Option<Vec<String>>,
-    pub external_account_required: Option<String>,
+    pub external_account_required: Option<bool>,
 }
 
 #[derive(Deserialize)]