docs: Update NEWS.md with zw-testframework refs (SiliconLabsSoftware#57)

For some reason those changes were not aligned from libs2 import.

Relate-to: SiliconLabsSoftware#50
Origin: SiliconLabsSoftware#57
Signed-off-by: Philippe Coval <philippe.coval@silabs.com>

Author: rzr

NEWS.md

@@ -11,6 +11,7 @@ Integrate internal changes progressively:
 
 ```
 applications/zpc/components/zwave/zwave_transports/s2/libs/zw-libs2: zw-libs2#zwave-sdk-7.21.0-ga-68-gbd9c072a
+applications/zpc/components/zwave/zwave_transports/s2/libs/zw-libs2/TestFramework: zw-testframework#zwave-sdk-7.20.0-ga-15-gccbd3fb
 ```
 
 ## ver_1.7.0