Update SECURITY.md

Author: antonmedv

SECURITY.md

@@ -12,8 +12,7 @@ unless this is not possible or feasible with a reasonable effort.
 | Version | Supported          |
 |---------|--------------------|
 | 8       | :white_check_mark: |
-| 7       | :white_check_mark: |
-| < 7     | :x:                |
+| <= 7    | :x:                |
 
 ## Reporting a Vulnerability