build(deps): bump Verify.SourceGenerators from 1.5.0 to 2.1.0 (#168)

Bumps [Verify.SourceGenerators](https://github.com/VerifyTests/Verify.SourceGenerators) from 1.5.0 to 2.1.0.
- [Release notes](https://github.com/VerifyTests/Verify.SourceGenerators/releases)
- [Commits](https://github.com/VerifyTests/Verify.SourceGenerators/commits)

---
updated-dependencies:
- dependency-name: Verify.SourceGenerators
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

src/Splat.DependencyInjection.SourceGenerator.Tests/Splat.DependencyInjection.SourceGenerator.Tests.csproj

@@ -12,7 +12,7 @@
     <PackageReference Include="xunit" Version="2.4.2" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.5" PrivateAssets="all" />
     <PackageReference Include="coverlet.msbuild" Version="6.0.0" />
-    <PackageReference Include="Verify.SourceGenerators" Version="1.5.0" />
+    <PackageReference Include="Verify.SourceGenerators" Version="2.1.0" />
     <PackageReference Include="ReactiveMarbles.SourceGenerator.TestNuGetHelper" Version="1.2.21" />
     <PackageReference Include="Verify.Xunit" Version="20.4.0" />
     <PackageRefernece Include="Microsoft.CodeAnalysis.CSharp" Version="3.10.0" PrivateAssets="all" />