add properties for IsLive and IsLegacy

EDPlayerJournal/Entries/FileHeaderEntry.cs

@@ -26,6 +26,22 @@ public class FileHeaderEntry : Entry {
     /// </summary>
     public string? Build { get; set; }
 
+    /// <summary>
+    /// Returns true if the version is legacy (3.X)
+    /// <summary>
+    public bool IsLegacy {
+        get {
+            return GameVersion.StartsWith("3.");
+        }
+    }
+
+    /// <summary>
+    /// Returns true if the version is live (4.x)
+    /// </summary>
+    public bool IsLive {
+        get { return !IsLegacy; }
+    }
+
     protected override void Initialise() {
         Part = JSON.Value<ulong?>("part") ?? 1;
         Language = JSON.Value<string?>("language") ?? string.Empty;