Bump Confluent.Kafka from 2.5.3 to 2.6.1 in /src

Bumps [Confluent.Kafka](https://github.com/confluentinc/confluent-kafka-dotnet) from 2.5.3 to 2.6.1.
- [Release notes](https://github.com/confluentinc/confluent-kafka-dotnet/releases)
- [Changelog](https://github.com/confluentinc/confluent-kafka-dotnet/blob/master/CHANGELOG.md)
- [Commits](confluentinc/confluent-kafka-dotnet@v2.5.3...v2.6.1)

---
updated-dependencies:
- dependency-name: Confluent.Kafka
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

src/ExeToProcessWithMultipleNative/ExeToProcessWithMultipleNative.csproj

@@ -14,7 +14,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Confluent.Kafka" Version="2.5.3" />
+    <PackageReference Include="Confluent.Kafka" Version="2.6.1" />
   </ItemGroup>
 
   <Target Name="EmbedLibrdkafkaRedistNativeLibraries_Net472" BeforeTargets="ResolvePackageAssets" Condition=" '$(TargetFramework)' == 'net472' ">