Pass through the CommandLineApplication return code

[dcsync]

Before applying this change SharpGen was always returning 0 on my
system.

[cobbr]

Hey @dcsync, thanks for the pull! (And sorry for the delayed response)

I was playing around with this, and I am still always getting a 0 exit code, even with your changes. Could you provide an example of when this is not the case?

[cobbr]

bump @dcsync

[dcsync]

Hey @cobbr, does it return 0 on your system when invalid arguments are passed? Here's how I'm testing it:

$ dotnet --version
2.2.105
$ dotnet ./bin/Debug/netcoreapp2.1/SharpGen_original.dll ; echo "exit code: $?"
The --file field is required.
Specify --help for a list of available options and commands.
exit code: 0

Before returning the exit code of app.Execute() it would always return 0 on build failures and when invalid arguments were passed. After patching it I was able to get non-zero exit codes:

$ dotnet ./bin/Debug/netcoreapp2.1/SharpGen_patched.dll ; echo "exit code: $?"
The --file field is required.
Specify --help for a list of available options and commands.
exit code: 1