Added flag if "Maintainer changes" appears in the PR body

[mwaddell]

closes #20

Ideally this would get passed over in the commit message instead of being part of the (editable) PR body, but that's not part of fetch-metadata or dependabot-core, so I can't modify that. So, in the meantime, we can just use the PR body.

[jeffwidman]

Sorry this took a while to review.

The logic all looks great. 👍

Three suggestions:

1. Write out the key as the full maintainerChanges
2. Add mention of it on the Readme?
3. Add mention of it in the action.yml as one of the outputs?

Also, I spent some time looking at whether we could move the logic that adds the "Maintainer changes" to the PR body from closed source into dependabot-core. It turns out that identifying the maintainer changes actually already happens in dependabot-core, but not at a place where we can easily add it to the commit body. So that's why even though it gets passed to the internal closed-source service to include as part of the PR body, it's not added to the commit itself.

Additionally, how the PR body gets built may get rejiggered since we're working on grouping of updates... so that's in flux a little. So for now scraping the PR body rather than pulling this off a structured metadata field is probably the best way.

[jeffwidman]

Really close, just a couple of minor comments

[jeffwidman]

Thank you!

[jeffwidman]

Can you rebase? It's out of date and since "allow maintainer changes" isn't checked, I can't rebase it myself...