Update changelog for v1.4

Signed-off-by: Peter Grayson <pete@jpgrayson.net>

CHANGELOG.md

@@ -1,6 +1,6 @@
 # Changelog
 
-## [Unreleased]
+## [1.4] 2021-10-27
 
 ### Removed
 - Python 3.5, which became EOL 2020-09-13, support is deprecated and
@@ -20,12 +20,18 @@
   importing patches from email (#42)
 - StGit works with Python 3.10
 - `stg version` prints a more abbreviated Python version
+- `stg commit` will no longer commit empty patches by default; the
+  `--allow-empty` option may be used to override this behavior (#158)
+- The `stgit.main.main()` function now takes an argv parameter and
+  returns an int return code in most cases instead of calling
+  sys.exit(), thus making main() a bit easier to use as an API.
 
 ### Fixed
 - Repair stack upgrade with `stg branch --list` (#155)
 - Repair crash in `stg squash` with out of order patches and no name
   specified (#157)
 - Zsh completions learn `stg float --noapply` option
+- Zsh completion for `stg sink` now allows multiple patches
 
 
 ## [1.3] 2021-09-26