update StackExchange version

Author: shacharPash

tests/NRedisStack.Tests/NRedisStack.Tests.csproj

@@ -20,7 +20,7 @@
     <PackageReference Include="Moq" Version="4.18.1" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.11.0" />
     <PackageReference Include="xunit.runner.visualstudio" Version="2.4.3" />
-    <PackageReference Include="StackExchange.Redis" Version="2.6.45" />
+    <PackageReference Include="StackExchange.Redis" Version="2.6.90" />
     <PackageReference Include="xunit" Version="2.4.1" />
     <PackageReference Include="xunit.assert" Version="2.4.1" />
   </ItemGroup>