Update test dependencies

Small C#13 modification

Author: monoman

Directory.Packages.props

@@ -5,9 +5,9 @@
     <NoWarn>$(NoWarn);NU1507</NoWarn>
   </PropertyGroup>
   <ItemGroup>
-    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.11.1" />
+    <PackageVersion Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
     <PackageVersion Include="NUnit" Version="4.2.2" />
-    <PackageVersion Include="NUnit.Analyzers" Version="4.3.0" />
+    <PackageVersion Include="NUnit.Analyzers" Version="4.4.0" />
     <PackageVersion Include="NUnit3TestAdapter" Version="4.6.0" />
     <PackageVersion Include="System.Drawing.Common" Version="8.0.10" />
   </ItemGroup>

SvgNet/ImplementedGraphics/SVGGraphics.cs

@@ -140,7 +140,7 @@ public SvgGraphics(Color backgroundColor) {
     public Point RenderingOrigin { get => throw new SvgGdiNotImplementedException("get_RenderingOrigin"); set { } }
 
     public SmoothingMode SmoothingMode {
-        get => _smoothingMode;
+        get;
         set {
             switch (value) {
                 case SmoothingMode.Invalid:
@@ -160,9 +160,9 @@ public SmoothingMode SmoothingMode {
                 default:
                     _cur.Style.Set("shape-rendering", "auto"); break;
             }
-            _smoothingMode = value;
+            field = value;
         }
-    }
+    } = SmoothingMode.Invalid;
 
     /// <summary>
     /// Get is not implemented (throws an exception).
@@ -1384,8 +1384,6 @@ public void SetClip(RectangleF rect) {
     private readonly MatrixStack _transforms;
     private SvgStyledTransformedElement _cur;
 
-    private SmoothingMode _smoothingMode = SmoothingMode.Invalid;
-
     private static void AddHatchBrushDetails(SvgPatternElement patty, SvgColor col, HatchStyle hs) {
         SvgStyledTransformedElement l1 = null;
         SvgStyledTransformedElement l2 = null;