Resolve the issue of upload failure

Author: chopin-fan

scripts/deploy_nuget.sh

@@ -27,7 +27,7 @@ do
             dotnet build ${name}/${name}.csproj /clp:ErrorsOnly --configuration Release -P:Version=${VERSION} -P:Authors=AElf -o ${build_output}
 
             echo `ls ${build_output}/${name}.${VERSION}.nupkg`
-            dotnet nuget push ${build_output}/${name}.${VERSION}.nupkg -k ${NUGET_API_KEY} -s https://api.nuget.org/v3/index.json
+            dotnet nuget push ${build_output}/${name}.${VERSION}.nupkg -k ${NUGET_API_KEY} -s https://api.nuget.org/v3/index.json  --skip-duplicate 
         fi
     done
     cd ../