docs: record 0.2.0 in the changelog on main (#37)

Two added lines: the `## [0.2.0] - 2026-09-09` heading and the now-empty
`[Unreleased]` above it. No note is edited, moved or reworded.

Verified rather than asserted: the resulting `## [0.2.0]` section is
byte-identical to the one at the `v0.2.0` tag, 204 lines, checked by
extracting both and diffing.

Byte-exactness is the rule here and it holds, unlike the 0.1.0
back-port. That one had to depart from it deliberately, because the
tagged section carried `Changed` and `Fixed` with a migration note on a
*first* release — deltas against pre-release states, meaningless to
anyone reading published notes. Nothing like that applies to 0.2.0: it
is a real delta against 0.1.0, its sections describe changes that
happened, and the migration notes have somewhere to migrate from. So
the copy is exact and any correction to these notes belongs in the
GitHub Release body rather than here.

The release flow still does not do this by itself — `cut-release` opens
a back-port PR that bumps POM versions and nothing else, and
`release.yml` reads the section on the release branch, which is deleted
post-tag. Third release in a row that needs this by hand.

Author: RobertoIskandarani

CHANGELOG.md

@@ -7,6 +7,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+## [0.2.0] - 2026-09-09
+
 ### Added
 
 - `JwksCache` and `MetadataCache` gained public constructors taking a `java.time.Clock`, so the