Bump Grpc.Tools from 2.67.0 to 2.68.1 (#2970)

Bumps [Grpc.Tools](https://github.com/grpc/grpc) from 2.67.0 to 2.68.1.
- [Release notes](https://github.com/grpc/grpc/releases)
- [Changelog](https://github.com/grpc/grpc/blob/master/doc/grpc_release_schedule.md)
- [Commits](https://github.com/grpc/grpc/commits)

---
updated-dependencies:
- dependency-name: Grpc.Tools
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

src/Directory.Build.props

@@ -40,7 +40,7 @@ Update all AWSSDK versions</PackageReleaseNotes>
         <MicrosoftExtensionsVersion>[6.0.*,)</MicrosoftExtensionsVersion>
         <AzureIdentityVersion>1.13.1</AzureIdentityVersion>
         <ProtobufVersion>3.27.3</ProtobufVersion>
-        <GrpcToolsVersion>2.67.0</GrpcToolsVersion>
+        <GrpcToolsVersion>2.68.1</GrpcToolsVersion>
     </PropertyGroup>
 
     <!-- SourceLink support for all Akka.NET projects -->