feat: add configFileName option

[markwhitfeld]

For projects that use multiple firebase.json files, it is essential to be able to specify the name of the file that the cli should use. This is available as the --config option in the firebase CLI. This PR adds a configFileName action option to set this parameter.

I opted for the configFileName option name over config to avoid any ambiguity that it should be a file name.

[markwhitfeld]

@jamesdaniels and @jhuleatt I wanted to make a few details explicit about the decisions I made in this PR...

I could have gone either way on the name of the option. There was a choice of:

• config: matches the argument that is passed to the firebase cli, but might be a bit ambiguous as to what config it is referring to in the context of a github action
• I had the thought of finding a more explicit name, but something like firebaseConfigJsonFileName is just a bit much😉 !
• configFileName: is clear that it is referring to a file name where the firebase config is held.
  • I also didn't want to promote the idea of providing a file path because it would make the entryPoint setup incorrect if you refer to any subpath. The firebase cli uses the config option to determine the project root and therefore would conflict with the expectations of the entryPoint option that was set for this action.

I settled on the configFileName option name.

[tayzlor]

👍 for this. We're deploying to firebase in a Monorepo with NX (and multiple firebase apps). This functionality would be hugely valuable. Seems like there is an (older) overlapping PR for this over here too https://github.com/FirebaseExtended/action-hosting-deploy/pull/153

[algoflows]

👍🏻 as well @jhuleatt this has been open for ages, any chance of a review merge?!

[markwhitfeld]

@jhuleatt I have resolved the merge conflicts. The PR is ready for review again 👍

[markwhitfeld]

Not wanting to nag, but who is overseeing this repo and can give some sort of response to this PR? I am an Open Source author myself and I understand that things get busy. Some sort of indication would be helpful though.