Bump Microsoft.CodeAnalysis.CSharp from 4.14.0 to 5.3.0

---
updated-dependencies:
- dependency-name: Microsoft.CodeAnalysis.CSharp
  dependency-version: 5.3.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

Directory.Packages.props

@@ -24,6 +24,6 @@
     <PackageVersion Include="NUnit3TestAdapter" Version="6.1.0" />
 
     <!-- To resolve dependency conflict with GirCore.GObject-2.0.Integration and BenchmarkDotNet -->
-    <PackageVersion Include="Microsoft.CodeAnalysis.CSharp" Version="4.14.0" />
+    <PackageVersion Include="Microsoft.CodeAnalysis.CSharp" Version="5.3.0" />
   </ItemGroup>
 </Project>

Pinta.Gui.Widgets/Pinta.Gui.Widgets.csproj

@@ -6,6 +6,7 @@
   <Import Project="../properties/ReferenceGirCoreGObject20Integration.props" />
 
   <ItemGroup>
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" VersionOverride="5.3.0" />
     <ProjectReference Include="..\Pinta.Core\Pinta.Core.csproj" />
   </ItemGroup>
 </Project>