Upgrade .net builder version

Dockerfile

@@ -1,3 +1,3 @@
-FROM mcr.microsoft.com/dotnet/core/sdk:3.0 AS builder
+FROM mcr.microsoft.com/dotnet/core/sdk:3.1 AS builder
 
 COPY . .

SuccessfulCodeTools/LowLevelHttpClient/CustomHttpClient.cs

@@ -61,7 +61,6 @@ namespace SuccessfulCodeTools.LowLevelHttpClient
                     return new CustomHttpResponseMessage(memory);
                 }
             }
-
         }
     }
 }