add push rule settings

Fixes #126

lib/models/requests/update_push_rule.dart

@@ -0,0 +1,27 @@
+import "package:freezed_annotation/freezed_annotation.dart";
+import "package:nexus/models/push_rules.dart";
+
+part "update_push_rule.freezed.dart";
+part "update_push_rule.g.dart";
+
+@Freezed(toJson: false, fromJson: false)
+@JsonSerializable()
+class const UpdatePushRuleRequest({
+  required final PushRuleKind kind,
+  required final String ruleId,
+  required final UpdatePushRuleAction action,
+
+  /// The new rule, when putting it. Only its actions and pattern are used.
+  final PushRule? newContent,
+
+  /// The new actions, when putting only them.
+  final PushActions? actions,
+}) with _$UpdatePushRuleRequest {
+  Map<String, Object?> toJson() => _$UpdatePushRuleRequestToJson(this);
+
+  factory UpdatePushRuleRequest.fromJson(Map<String, Object?> json) =>
+      _$UpdatePushRuleRequestFromJson(json);
+}
+
+@JsonEnum(fieldRename: .snake)
+enum UpdatePushRuleAction { enable, disable, put, putActions, delete }