Packages added to elm-package.json even when they are not successfully installed

[kevgathuku]

I was trying to install the elm-community/elm-history -y to an Elm project I'm working on.
I ran this command:
elm-package install elm-community/elm-history -y
and got this error message:

Error: I cannot find a set of packages that works with your constraints.

--> There are no versions of elm-community/elm-history that work with Elm
    0.18.0. Maybe the maintainer has not updated it yet.

I found its GitHub repo and saw that the package was deprecated.
However, the package was still added to the elm-package.json file even though it was not successfully installed.

This makes subsequent runs of elm-package install fail because I now have an invalid package in the elm-package.json file.

Expected Behaviour:
The invalid package name should not be added to the elm-package.json file

This is on elm-package 0.18.0

[process-bot]

Thanks for the issue! Make sure it satisfies this checklist. My human colleagues will appreciate it!

Here is what to expect next, and if anyone wants to comment, keep these things in mind.

[ceddlyburge]

I experienced this also.