[DX Streamline] Build CHANGELOG incrementally

[BigLep]

Problem to solve

When performing a Lotus a release, a non-trivial amount of time is spent at the end assembling, coalescing, and editorializing the CHANGELOG/release notes. The problem with this is:

1. It often taking a non-trivial amount of time
2. Usually the team isn't early or ahead of schedule when it starts the release process, so this non-trivial variable at the end is either stressful and/or becomes a blocking/delaying step of the release.
3. The person attempting to do the release (e.g., "release engineer" like @rjan90) isn't always close to all the development work to properly summarize and highlight changes.

Why Important

If the project has goals of releasing more frequently while still keeping a high quality level (as discussed in #12020), then it helps to have more predictability, especially at the end of the development cycle.

User/Customer

Lotus maintainers

Notes

Idea: ipfs/kubo took the path of requiring a changelog update with each PR by default (although there are self-service ways to opt out of this for a given PR). See ipfs/boxo#398 . This had the benefit of:

1. Build the changelog incrementally
2. Have the subject matter experts help document since they are mostly likely best positioned to highlight the importance or caveats of a certain change.