Add change log entry

Signed-off-by: Carmen Bianca BAKKER <carmenbianca@fsfe.org>

CHANGELOG.md

@@ -51,10 +51,13 @@ The versions follow [semantic versioning](https://semver.org).
   (#645).
 - `--add-license-concluded`, `--creator-person`, and `--creator-organization`
   added to `reuse spdx`. (#623)
+- Added `--contributor` option to `annotate`. (#669)
 
 ### Changed
 
 - Bumped SPDX license list to v3.20. (#692)
+- `reuse.SpdxInfo` is now a (frozen) dataclass instead of a namedtuple. This is
+  only relevant if you're using reuse as a library in Python. (#669)
 - Sphinx documentation: Switched from RTD theme to Furo. (#673, #716)
 
 ### Deprecated