Follow the convention to set default values

Author: Jericho

src/GitReleaseManager.Core/Configuration/Config.cs

@@ -29,6 +29,8 @@ public Config()
                 AllowUpdateToPublishedRelease = false,
                 AllowMilestonesWithoutIssues = false,
                 IncludeContributors = false,
+                SortIssuesBy = Model.SortIssuesBy.Id,
+                SortIssuesDirection = Model.SortDirection.Ascending,
             };
 
             Export = new ExportConfig

src/GitReleaseManager.Core/Configuration/CreateConfig.cs

@@ -43,9 +43,9 @@ public class CreateConfig
         public bool IncludeContributors { get; set; }
 
         [YamlMember(Alias = "sort-issues-by")]
-        public SortIssuesBy SortIssuesBy { get; set; } = SortIssuesBy.Id;
+        public SortIssuesBy SortIssuesBy { get; set; }
 
         [YamlMember(Alias = "sort-issues-direction")]
-        public SortDirection SortIssuesDirection { get; set; } = SortDirection.Ascending;
+        public SortDirection SortIssuesDirection { get; set; }
     }
 }