fix: set header date formatter options

MastodonSDK/Sources/MastodonSDK/API/Mastodon+API+Timeline.swift

@@ -91,9 +91,3 @@ extension Mastodon.API.Timeline {
         }
     }
 }
-
-extension Bool {
-    var queryItemValue: String {
-        return self ? "true" : "false"
-    }
-}

MastodonSDK/Sources/MastodonSDK/API/Mastodon+API.swift

@@ -11,7 +11,11 @@ import enum NIOHTTP1.HTTPResponseStatus
 extension Mastodon.API {
         
     static let timeoutInterval: TimeInterval = 10
-    static let httpHeaderDateFormatter = ISO8601DateFormatter()
+    static let httpHeaderDateFormatter: ISO8601DateFormatter = {
+        var formatter = ISO8601DateFormatter()
+        formatter.formatOptions.insert(.withFractionalSeconds)
+        return formatter
+    }()
     static let encoder: JSONEncoder = {
         let encoder = JSONEncoder()
         encoder.dateEncodingStrategy = .iso8601

MastodonSDK/Sources/MastodonSDK/Entity/Mastodon+Entity+Toot.swift

@@ -18,7 +18,7 @@ extension Mastodon.Entity {
         public let content: String
         public let account: User
         
-        public let language: String
+        public let language: String?
         public let visibility: String
         
         enum CodingKeys: String, CodingKey {

MastodonSDK/Sources/MastodonSDK/Extension/Bool.swift

@@ -0,0 +1,14 @@
+//
+//  Bool.swift
+//  
+//
+//  Created by MainasuK Cirno on 2021/1/27.
+//
+
+import Foundation
+
+extension Bool {
+    var queryItemValue: String {
+        return self ? "true" : "false"
+    }
+}