Add 3.20.0 to CHANGELOG

Author: mrnugget

CHANGELOG.md

@@ -13,6 +13,14 @@ All notable changes to `src-cli` are documented in this file.
 
 ### Added
 
+### Changed
+
+### Fixed
+
+## 3.20.0
+
+### Added
+
 - Campaigns specs now include an optional `author` property. (If not included, `src campaigns` generates default values for author name and email.) `src campaigns` now includes the name and email in all changeset specs that it generates.
 - The campaigns temp directory can now be overwritten by using the `-tmp` flag with `src campaigns [apply|preview]` or by setting `SRC_CAMPAIGNS_TMP_DIR`. The directory is used to, for example, store log files and unzipped repository archives when executing campaign specs.