fix: /diag behaves like a proper boolean switch

before fix, order of arguments mattered:
- unless /diag is last argument, it is ignored; and the following
  argument is swalloed silently

/diag /l gv.log  -> diagnostic switch is ignored, no log file is created
/l console /diag -> diagnostic output is emitted to console
/l gv.log /diag  -> diagnostic output is emitted to log file

Author: davidjenni

src/GitVersion.App/ArgumentParser.cs

@@ -212,11 +212,7 @@ private static bool ParseSwitches(Arguments arguments, string? name, IReadOnlyLi
 
         if (name.IsSwitch("diag"))
         {
-            if (value?.IsTrue() != false)
-            {
-                arguments.Diag = true;
-            }
-
+            arguments.Diag = true;
             return true;
         }
 

src/GitVersion.App/ArgumentParserExtensions.cs

@@ -73,7 +73,7 @@ public bool IsSwitch(string switchName)
 
         public bool ArgumentRequiresValue(int argumentIndex)
         {
-            var booleanArguments = new[] { "updateassemblyinfo", "ensureassemblyinfo", "nofetch", "nonormalize", "nocache", "allowshallow" };
+            var booleanArguments = new[] { "updateassemblyinfo", "ensureassemblyinfo", "nofetch", "nonormalize", "nocache", "allowshallow", "diag" };
 
             var argumentMightRequireValue = !booleanArguments.Contains(singleArgument[1..], StringComparer.OrdinalIgnoreCase);