feat!: convert projects to .net 5 wip

Habittodo.Model/Due.cs

@@ -0,0 +1,24 @@
+using Newtonsoft.Json;
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Text;
+
+namespace Habittodo.Model
+{
+    public class Due
+    {
+        [JsonProperty("date")]
+        public string Date { get; set; }
+        [JsonProperty("timezone")]
+        public string Timezone { get; set; }
+        [JsonProperty("string")]
+        public string @String { get; set; }
+
+        public string ToJavaScriptDateStr()
+        {
+            try { return Date + "T00:00:00.000Z"; } catch { }
+            return null;
+        }
+    }
+}