chore(deps): update dependency system.reactive to 6.1.0

Author: renovate[bot]

src/ReactiveMarbles.CacheDatabase.Core/ReactiveMarbles.CacheDatabase.Core.csproj

@@ -8,6 +8,6 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.Bcl.AsyncInterfaces" Version="9.0.8" />
-    <PackageReference Include="System.Reactive" Version="6.0.1" />
+    <PackageReference Include="System.Reactive" Version="6.1.0" />
   </ItemGroup>
 </Project>