Update security policy wrt supported patch releases

SECURITY.md

@@ -6,12 +6,15 @@ Eclipse RDF4J follows the [Eclipse Vulnerability Reporting Policy](https://www.e
 
 Eclipse RDF4J supports security updates for the following releases:
 
+
 | Version | Supported          |
 | ------- | ------------------ |
-| 4.1.x   | ✅ |
-| 4.0.x   | ✅                 |
-| 3.7.x   | ✅                 |
-| < 3.7   | :x:                |
+| current release   | ✅ |
+| latest minor release before the current   | ✅(on request only) |
+| latest major release before the current   | ✅(on request only) |
+| anything older   | :x:                |
+
+For example if the current release is 4.1, we support security patches for 4.1.x (the current release) and 4.0.x (latest minor before current), as well as for 3.7.x (latest major before current), but not for 3.6.x or older. Security patches for the current release are provided proactively by the team, while patches for older supported releases are provided on request only.
 
 ## Reporting a Vulnerability