Update .gitlab-ci.yml image to mcr.microsoft.com/dotnet/sdk:5.0
Update .gitlab-ci.yml image to mcr.microsoft.com/dotnet/sdk:5.0 to match csproj and Microsoft's new convention for dotnet
Update .gitlab-ci.yml image to mcr.microsoft.com/dotnet/sdk:5.0 to match csproj and Microsoft's new convention for dotnet