Add minimal Electron dependencies

[malept]

Fixes #89.

[malept]

Evidently I need to figure out how to put a newer version of RPM onto the CI worker.

[fcastilloec]

I once attempted to do this for a different project. But given that rpm has many dependencies, it's not easy at all. The best thing we can do is use a Docker image based on Ubuntu 18.04, which is an LTS version that has a newer rpm, or use a Fedora image.
As an alternative, we can use an older electron when testing (<= 1.4.1) so trash dependencies don't cause a problem. If so, we should export trashRequiresAsBoolean and test it given that all other tests will be based on older electron versions.

Many people might use this module with Travis to test their apps, or they might just be stuck in an older version of Ubuntu (<= 18.04). Making this module explicitly require rpm >= 4.13 will break a lot of the builds out there, including some of my own projects (will electron-forge be affected?). People can use an old version, but I believe that it's better if we make it compatible.
The best I can think of is checking which version of rpm is being used and produce a warning saying that trash dependencies won't be added to the required packages, which will let the module build the rpm. Not all apps using electron are going to need to manipulate files and use the trash dependencies, so not having them explicitly mention won't affect the majority of projects out there.

Ubuntu Trusty will stop being supported next April; hopefully, Travis will add support for Bionic when this happens (rather than just keep Xenial-only images), in which case we won't need the warning anymore.

[malept]

The best I can think of is checking which version of rpm is being used and produce a warning saying that trash dependencies won't be added to the required packages, which will let the module build the rpm. Not all apps using electron are going to need to manipulate files and use the trash dependencies, so not having them explicitly mention won't affect the majority of projects out there.

👍 this is what I did.

will electron-forge be affected?

Yes. That's the main reason why I'm backporting a "good" version of RPM. Forge always runs against the latest stable version of Electron,and I'd rather not have the warning in CI. I've successfully built RPM 4.13.0.1 on xenial, I just need to remember how to publish a PPA.

[fcastilloec]

The only required change is adding that sentence to the README, the others can be fixed here or in another PR since they are dependent on changes to -common module

Regarding the PPA, that's a great idea. I remember I created a apt repository for some installers, but never a PPA. Let me know when you've done it, I would love to use it on some of my other projects

[malept]

Let me know when you've done it, I would love to use it on some of my other projects

I don't remember if I updated on this front. I couldn't get a PPA working for whatever reason (no error messages on the Launchpad side), so I ended up making an Ubuntu repo on bintray.

[fcastilloec]

We haven't updated it on this module yet. Travis is still using rpm from the Ubuntu repos. We need to add your bintray repo to Travis to stop the warning messages.
It'll be great if we had a PPA, but any repo is fine. I also had some trouble with Launchpad so I host PPA on Github on the gh-pages branch. For any outside repo, we also need to add gpg keys for it.

[malept]

We need to add your bintray repo to Travis to stop the warning messages.

I don't think it's necessary. It's not causing the builds to fail, and we're already running with DEBUG=electron-installer-redhat, which is a lot of noise to begin with.

For any outside repo, we also need to add gpg keys for it.

Yes, see: electron-userland/electron-forge-container@5847481