update changelog

CHANGELOG.md

@@ -8,12 +8,11 @@ and uses [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## [Unreleased]
 ### Changed
-* [651](https://github.com/dbekaert/RAiDER/pull/651) - Removed use of deprecated argument to `pandas.read_csv`.
-### Fixed
 * [657](https://github.com/dbekaert/RAiDER/pull/657) - Fixed a few typos in `README.md`.
 * [651](https://github.com/dbekaert/RAiDER/pull/651) - Removed use of deprecated argument to `pandas.read_csv`.
 * [627](https://github.com/dbekaert/RAiDER/pull/627) - Made Python datetimes timezone-aware and add unit tests and bug fixes.
 * [662](https://github.com/dbekaert/RAiDER/pull/662) - Ensures dem-stitcher to be >= v2.5.6, which updates the url for reading the Geoid EGM 2008.
+* [661](https://github.com/dbekaert/RAiDER/pull/661) - Fix bug in raiderDownloadGNSS, remove call to scipy.sum, and add unit tests
 
 ## [0.5.1]
 ### Changed