Bump SixLabors.ImageSharp from 3.1.7 to 3.1.11

---
updated-dependencies:
- dependency-name: SixLabors.ImageSharp
  dependency-version: 3.1.11
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

build/Directory.Build.props

@@ -144,7 +144,7 @@
 
   <!-- Needed for deterministic builds -->
   <ItemGroup>
-    <SourceRoot Include="$(MSBuildThisFileDirectory)..\"/>
+    <SourceRoot Include="$(MSBuildThisFileDirectory)..\" />
   </ItemGroup>
 
   <!--

samples/ComputeSharp.ImageProcessing/ComputeSharp.ImageProcessing.csproj

@@ -9,7 +9,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <PackageReference Include="SixLabors.ImageSharp" Version="3.1.7" />
+    <PackageReference Include="SixLabors.ImageSharp" Version="3.1.11" />
   </ItemGroup>
 
   <ItemGroup>