Fixed API compatibility issue

Source/QuestPDF/Helpers/CompilerFeatureRequiredAttribute.cs

@@ -1,20 +0,0 @@
-#if !NET7_0_OR_GREATER
-
-namespace System.Runtime.CompilerServices
-{
-    [AttributeUsage(AttributeTargets.All, AllowMultiple = true, Inherited = false)]
-    public sealed class CompilerFeatureRequiredAttribute : Attribute
-    {
-        public const string RefStructs = nameof(RefStructs);
-        public const string RequiredMembers = nameof(RequiredMembers);
-        public CompilerFeatureRequiredAttribute(string featureName)
-        {
-            FeatureName = featureName;
-        }
-        
-        public string FeatureName { get; }
-        public bool IsOptional { get; init; }
-    }
-}
-
-#endif