feature: Allow overriding with other env files

[e-e]

Instead of managing multiple env files with duplicate data, this adds a way to provide additional env files to use as overrides. The idea here being that there would be a "base" env file, and then environment-specific env files which would override a subset of the base env file values.

There were some auto-formatting changes, but I tried to run them against dartfmt and it said there were no changes to be made 🤷

[java-james]

Thanks for the PR just a note to say aware it's open and will make time to review and see how this aligns with larger .env libraries in regards to usage

[e-e]

Hey @java-james. No pressure on the PR, but just wanted to report back that we are currently successfully using this addition in our app

[SAGV]

This would be so good to have!

[java-james]

@e-e are you interested and available to update this PR to resolve existing conflicts?

[SAGV]

Would be really nice to have it to work!

[e-e]

@java-james Hey! I won't have time to look at this for the foreseeable future, so if someone else wants to take it on by all means

[StephenBrough]

@java-james @e-e I think I've fixed the conflicts. What's the best way to send the fixes up?

[e-e]

@StephenBrough

do you want to open a pull request against my fork?

[e-e]

@java-james sorry for the delay. Thanks to @StephenBrough the conflicts have been resolved

[java-james]

Beauty, thanks. I will get this reviewed.

[java-james]

I have reviewed this PR and am happy with the additional feature. Agree that it's an additional useful way to load/compose your env variables.

edit: I was able to resolve the conflict in browser :)

Waiting for workflows to run now

[java-james]

Merged. Thanks for the contribution