support first placeholder & overwriting version

ModpackUpdater.Apps.Client/Form1.cs

@@ -146,7 +146,8 @@ public partial class Form1
     {
         var updater = new ModpackInstaller(updateConfig, modpackInfo)
         {
-            OverwriteRefTag = Program.Options.RefTag
+            OverwriteRefTag = Program.Options.RefTag,
+            OverwriteVersion = Program.Options.Version,
         };
         updater.InstallProgessUpdated += Update_InstallProgessUpdated;
         updater.CheckingProgressUpdated += Updated_CheckingProgresssUpdated;

ModpackUpdater.Apps.Client/Options.cs

@@ -12,6 +12,7 @@ internal class Options
     public bool Silent { get; private set; }
     public bool NoUi { get; private set; }
     public string RefTag { get; private set; }
+    public string Version { get; private set; }
     public UpdateCheckOptionsAdv UpdateOptions { get; } = new();
 
     public Options(string[] args)
@@ -29,7 +30,8 @@ internal class Options
             { "m|maintenance", "Ignores the maintenance mode.", m => UpdateOptions.IgnoreMaintenance = true},
             { "i|nonpublic", "Include non public (currently hidden) updates.", i => UpdateOptions.IncludeNonPublic = true},
             { "k|key=", "An key for retriving extra files on updates.", k => UpdateOptions.ExtrasKey = k},
-            { "r|reftag=", "Force uses a specific version, if supported.", r => RefTag = r},
+            { "r|reftag=", "Force uses a specific reference tag, if supported.", r => RefTag = r},
+            { "v|version=", "Force uses a specific version, if supported.", v => Version = v},
         };
 
         additionals.AddRange(options.Parse(args));

ModpackUpdater.Apps.Client/Program.cs

@@ -106,6 +106,7 @@ public static class Program
         var installer = new ModpackInstaller(config, info)
         {
             OverwriteRefTag = Options.RefTag,
+            OverwriteVersion = Options.Version,
             Log = Log,
         };
         var result = installer.Check(updateOptions).Result;