Rename variable default value to value

src/modules/Elsa.Workflows.Core/Activities/ParallelForEach.cs

@@ -26,7 +26,7 @@ public class ParallelForEach<T> : Activity
             // For each item, declare a new block of memory to store the item into.
             var localVariable = new Variable<T>()
             {
-                DefaultValue = item
+                Value = item
             };
 
             if (CurrentValue != null)

src/modules/Elsa.Workflows.Core/Models/Variable.cs

@@ -16,14 +16,14 @@ public class Variable : MemoryReference
         Name = name;
     }
 
-    public Variable(string name, object? defaultValue = default) : this(name)
+    public Variable(string name, object? value = default) : this(name)
     {
-        DefaultValue = defaultValue;
+        Value = value;
     }
 
     public string? Name { get; set; }
-    public object? DefaultValue { get; set; }
-    public override MemoryBlock Declare() => new(DefaultValue);
+    public object? Value { get; set; }
+    public override MemoryBlock Declare() => new(Value);
 }
 
 public class Variable<T> : Variable
@@ -42,7 +42,7 @@ public class Variable<T> : Variable
     
     public Variable(T value)
     {
-        DefaultValue = value;
+        Value = value;
     }
 
     public T? Get(ActivityExecutionContext context) => Get(context.ExpressionExecutionContext).ConvertTo<T?>();