Failing when update is available for CI integration

[andmos]

It would be great with some switch/flag that changed the exitcode if an update is available for any package in a csproj or nuspec file. In that way, a CI build could be set up to run frequently and fail if an update is available that should be looked at.
Something like this should do the trick:

$ dotnet-deps
We found 7 😢 dependencies. For 🍺, type 'deps --update'
$ echo $?
1

That will integrate quite well with any CI tool.

[seesharper]

Closing this by #7 for now. Feel free to reopen if the need for a custom exit code should arise 👍