Bump Grpc.Tools in /src/clustering/sharding-sqlserver (#227)

Bumps [Grpc.Tools](https://github.com/grpc/grpc) from 2.66.0 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/clustering/sharding-sqlserver/SqlSharding.Shared/SqlSharding.Shared.csproj

@@ -9,7 +9,7 @@
     <ItemGroup>
         <PackageReference Include="Akka.Cluster.Sharding" Version="$(AkkaVersion)" />
         <PackageReference Include="Akka.Cluster.Hosting" Version="$(AkkaHostingVersion)" />
-        <PackageReference Include="Grpc.Tools" Version="2.66.0">
+        <PackageReference Include="Grpc.Tools" Version="2.68.1">
             <PrivateAssets>all</PrivateAssets>
             <IncludeAssets>runtime; build; native; contentfiles; analyzers; buildtransitive</IncludeAssets>
         </PackageReference>