Use GitHub releases to track official releases.

[gregturn]

Add a changelog to track issues on a per-milestone basis.

[wilkinsona]

Can we please use GitHub releases for this? It's where (almost?) every other Spring project publishes its changelog. It's also increasingly common across the broader ecosystem. Consistency is really beneficial to our users as it means there's only one place for them to learn to look.

[gregturn]

Pivot from publishing changelog reports inside releases to using GitHub releases.