chore(deps): update dotnet monorepo to 4.12.0 (#148)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

src/ReactiveUI.SourceGenerator.Tests/ReactiveUI.SourceGenerators.Tests.csproj

@@ -22,11 +22,11 @@
     <PackageReference Include="Verify.Xunit" />
     <PackageReference Include="Verify.SourceGenerators" />
     <PackageReference Include="Basic.Reference.Assemblies.Net80" />
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" PrivateAssets="all" VersionOverride="4.11.0" />
-    <PackageReference Include="Microsoft.CodeAnalysis.Common" PrivateAssets="all" VersionOverride="4.11.0" />
-    <PackageReference Include="Microsoft.CodeAnalysis.Workspaces.Common" PrivateAssets="all" VersionOverride="4.11.0" />
-    <PackageReference Include="Microsoft.CodeAnalysis" PrivateAssets="all" VersionOverride="4.11.0" />
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" PrivateAssets="all" VersionOverride="4.11.0" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp" PrivateAssets="all" VersionOverride="4.12.0" />
+    <PackageReference Include="Microsoft.CodeAnalysis.Common" PrivateAssets="all" VersionOverride="4.12.0" />
+    <PackageReference Include="Microsoft.CodeAnalysis.Workspaces.Common" PrivateAssets="all" VersionOverride="4.12.0" />
+    <PackageReference Include="Microsoft.CodeAnalysis" PrivateAssets="all" VersionOverride="4.12.0" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" PrivateAssets="all" VersionOverride="4.12.0" />
     <PackageReference Include="FluentAssertions" />
   </ItemGroup>