fix security policy: 1.4.x is security supported

SECURITY.md

@@ -4,12 +4,12 @@
 
 These borg releases are currently supported with security updates.
 
-| Version | Supported              |
-|---------|------------------------|
-| 1.4.x   | :x: (not released yet) |
-| 1.2.x   | :white_check_mark:     |
-| 1.1.x   | :x:                    |
-| < 1.1   | :x:                    |
+| Version | Supported          |
+|---------|--------------------|
+| 1.4.x   | :white_check_mark: |
+| 1.2.x   | :white_check_mark: |
+| 1.1.x   | :x:                |
+| < 1.1   | :x:                |
 
 ## Reporting a Vulnerability