Nudging to 5.15.0 (#475)

Author: cskardon

Neo4jClient/Neo4jClient.csproj

@@ -22,7 +22,7 @@
     <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
       <PackageReference Include="Microsoft.CSharp" Version="4.7.0" />
       <PackageReference Include="Microsoft.VisualBasic" Version="10.3.0" />
-      <PackageReference Include="Neo4j.Driver.Signed" Version="5.14.0" />
+      <PackageReference Include="Neo4j.Driver.Signed" Version="5.15.0" />
       <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
       <PackageReference Include="System.ComponentModel.Annotations" Version="5.0.0" />
       <PackageReference Include="System.Dynamic.Runtime" Version="4.3.0" />