Update CHANGELOG.md to include current PR

Co-authored-by: Brewster Malevich <[email protected]>

Author: JMGilbert

CHANGELOG.md

@@ -6,7 +6,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 ### Fixed
-- Fix issue [#45](https://github.com/ClimateImpactLab/dscim/issues/45) by allowing for `emission_scenario` to be `None`. ([PR #46](https://github.com/ClimateImpactLab/dscim/pull/46), [@JMGilbert](https://github.com/JMGilbert))
+- Fix issue [#45](https://github.com/ClimateImpactLab/dscim/issues/45) by allowing for `emission_scenario` to be `None`. ([PR #46](https://github.com/ClimateImpactLab/dscim/pull/46), [PR #47](https://github.com/ClimateImpactLab/dscim/pull/47), [@JMGilbert](https://github.com/JMGilbert))
 
 ## [0.2.0] - 2022-09-16
 ### Changed