chore: release Gateway, headless-client and GUI client (#7903)

This bumps the versions of Gateway, headless-client and the GUI client
as well as updates the respective changelogs. These have been released
today:

- https://github.com/firezone/firezone/releases/tag/gui-client-1.4.1
- https://github.com/firezone/firezone/releases/tag/gateway-1.4.3
-
https://github.com/firezone/firezone/releases/tag/headless-client-1.4.1

It is all done in one PR to avoid merge conflicts within the updates of
the Makefile.

scripts/Makefile

@@ -20,16 +20,16 @@
 # Tracks the current version to use for generating download links and changelogs
 current-apple-version = 1.4.0
 current-android-version = 1.4.0
-current-gateway-version = 1.4.2
-current-gui-version = 1.4.0
-current-headless-version = 1.4.0
+current-gateway-version = 1.4.3
+current-gui-version = 1.4.1
+current-headless-version = 1.4.1
 
 # Tracks the next version to release for each platform
 next-apple-version = 1.4.1
 next-android-version = 1.4.1
-next-gateway-version = 1.4.3
-next-gui-version = 1.4.1
-next-headless-version = 1.4.1
+next-gateway-version = 1.4.4
+next-gui-version = 1.4.2
+next-headless-version = 1.4.2
 
 # macOS uses a slightly different sed syntax
 ifeq ($(shell uname),Darwin)