Cloudevent example use official image

[subfuzion]

This example updates examples/raw_cloudevent. It also addresses an issue I noted because we weren't committing pubspec.lock files with the sample apps. It removes the top level .gitignore and .dockerignore files and places them individually tailored for the library packages and sample applications.

Closes #229

[domesticmouse]

=)

[kevmoo]

I'm...ambivalent about including the lock files here.

That means we'll have to update these ~often or users won't be getting the latest dependencies.

[subfuzion]

I see your point of view. We already had a separate discussion with @mit-mit and I also agreed with following recommended best practices for apps and committing the lock file. When we don't, we run into issues like I did with #229 where a lock file on the users system is out-of-date (and isn't overwritten when pulling the latest). This PR is merged, so let's can continue the discussion in a new issue.

[mit-mit]

Why are you ambivalent @kevmoo? These are apps, right?

[kevmoo]

Why are you ambivalent @kevmoo? These are apps, right?

Yes...but they are samples. "pinning" deps for something actively maintained in a team totally makes sense.

For samples...it feels weird.

[mit-mit]

Say more. How does it feel weird? Is there some practical issue?

[kevmoo]

Say more. How does it feel weird? Is there some practical issue?

Sorry for being vague.

We want our users to get the latest dependencies, generally. For a deployed app, saving the .lock file makes sense.

This seems like noise. PRs that are just "update deps" are noisy. maybe it's just something I need to get used to. It's a feeling at the moment, but I don't have anything specific to pin it on. Sorry! 🤷