`latest` tag is not getting updated in mcr.microsoft.com/dotnet/core-nightly/runtime-deps

[MichaelSimons]

The mcr.microsoft.com/dotnet/core-nightly/runtime-deps:latest tag has not been updated since 2020-05-07.

> docker pull mcr.microsoft.com/dotnet/core-nightly/runtime-deps:latest
latest: Pulling from dotnet/core-nightly/runtime-deps
54fec2fa59d0: Pull complete
f685ad152116: Pull complete
Digest: sha256:d2c84b0b046a813a8813bef034e5646ecf1d715514bbf6cad3e815899d45bda7
Status: Downloaded newer image for mcr.microsoft.com/dotnet/core-nightly/runtime-deps:latest
mcr.microsoft.com/dotnet/core-nightly/runtime-deps:latest
> docker inspect mcr.microsoft.com/dotnet/core-nightly/runtime-deps:latest -f "{{ .Created }}"
2020-05-07T00:24:17.813296738Z

This is only an issue in the nightly repo

FYI, I discovered this while reviewing #2306. I diffed master and nightly to see the differences between the two branches.

[mthalman]

Fixed by #2340.