fix: FroniusSolarClient/FroniusSolarClient.csproj to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-DOTNET-NEWTONSOFTJSON-2774678

Author: snyk-bot

FroniusSolarClient/FroniusSolarClient.csproj

@@ -25,7 +25,7 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.Extensions.Logging" Version="2.2.0" />
-    <PackageReference Include="Newtonsoft.Json" Version="12.0.2" />
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
   </ItemGroup>
 
 </Project>