update release-notes.txt

Author: romain-grecourt

release-notes.txt

@@ -55,3 +55,7 @@ JSFTemplating 2.1.1
 - Move the build system to Maven 3.x
 - Updated the Annotation Processor to JSR 169 in order to support JSK8 (APT has been removed effectively in JDK8).
 - refactored events and task to match the state of com.sun.jsft in version 2.1.0.
+
+JSFTemplating 2.1.2
+============================================================
+- Relaxed OSGi import for javax.servlet.* to "[3.0,5)"