improve process document and release notes script

[kailuowang]

fixes #2879

There are some minor review process clarifications here as well.
namely from

When fixing typos or improving documentation only one sign-off is
required (although for major edits waiting for two may be preferable).

to

When fixing typos, improving documentation or minor build fix only 
one sign-off is required (although for major edits waiting for two
 may be preferable).

[codecov-io]

Codecov Report

Merging #2881 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #2881   +/-   ##
=======================================
  Coverage   94.21%   94.21%           
=======================================
  Files         368      368           
  Lines        6948     6948           
  Branches      308      308           
=======================================
  Hits         6546     6546           
  Misses        402      402

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[travisbrown]

Is it too late to be consistent about case for labels? I know it's silly but looking at this list is extremely painful to me.

[kailuowang]

IIRC, it's easy to change label text retrospectively. However, the intention for the case choice for breaking-change labels is for them to stand out as they often deserve more attention from users. We used color as well but there are users that are color blinded.

[travisbrown]

I'm vaguely 👎 on this. I don't think releases happen often enough to need all this automation, and would rather have hand-written release notes that can provide some synthesis, emphasis, etc. On a pettier note I'm also still 👎 on the inconsistently-cased labels. If everyone else wants to approve it, go for it, but I'd rather not.

[djspiewak]

I'm 👍 on all of this except for the inconsistent label casing. I'd prefer if everything were just entirely lower-case.

[kailuowang]

@travisbrown on your first objection, I would like to clarify that this process does not automatically publish the release note. The release note script merely generates a draft and the maintainer still have to copy paste and edit, if necessary, it. The process also makes the history of PRs on GitHub a lot more organized and searchable through milestones and labels.

[rossabaker]

I'm fine with it. I agree with Travis on hand tweaking, and I don't want to ever badger new contributors for pristine titles on PRs to support pristine automated changelogs. But it's also tedious to assemble them after the fact, so I appreciate the tools to get a baseline.

The inconsistent casing also makes me cringe, but I won't stand in the way of progress over it.