Update MCUboot version to latest

Pick up latest version which contains all features
which were upstreamed from TF-M MCUboot fork.

Change-Id: I99c4ee95758738b8878ad545380224ba4c5c2115
Signed-off-by: Tamas Ban <tamas.ban@arm.com>
diff --git a/jenkins/cppcheck.jpl b/jenkins/cppcheck.jpl
index 6a6d2cb..3223ac9 100644
--- a/jenkins/cppcheck.jpl
+++ b/jenkins/cppcheck.jpl
@@ -50,7 +50,7 @@
           $class: 'GitSCM',
           branches: [[name: 'FETCH_HEAD']],
           userRemoteConfigs: [[
-            refspec: 'refs/tags/$MCUBOOT_VERSION',
+            refspec: '$MCUBOOT_REFSPEC',
             url: params.MCUBOOT_URL
           ]]
         ]