Docker image certificate issue

[darrencauthon]

http://www.mono-project.com/docs/about-mono/releases/3.12.0/#cert-sync

http://www.mono-project.com/docs/faq/security/

 ---> 3f629e821e04
Removing intermediate container d73c363a1d2d
Step 5 : RUN nuget update -self
 ---> Running in 7919caa87365
Added file 'NuGet.Config' to folder '/root/.config/NuGet'.
Checking for updates from https://www.nuget.org/api/v2/.
Currently running NuGet.exe 2.12.0.
Updating NuGet.exe to 3.4.4-rtm-final.
Error: TrustFailure (The authentication or decryption has failed.)
The command '/bin/sh -c nuget update -self' returned a non-zero code: 1