scripts: Show image version while verifying

Change adds showing image version while verifying.

Signed-off-by: Marek Pieta <Marek.Pieta@nordicsemi.no>
diff --git a/scripts/imgtool/main.py b/scripts/imgtool/main.py
index b4ae0c1..5ed4daa 100755
--- a/scripts/imgtool/main.py
+++ b/scripts/imgtool/main.py
@@ -109,9 +109,10 @@
 @click.command(help="Check that signed image can be verified by given key")
 def verify(key, imgfile):
     key = load_key(key) if key else None
-    ret = image.Image.verify(imgfile, key)
+    ret, version = image.Image.verify(imgfile, key)
     if ret == image.VerifyResult.OK:
         print("Image was correctly validated")
+        print("Image version: {}.{}.{}+{}".format(*version))
         return
     elif ret == image.VerifyResult.INVALID_MAGIC:
         print("Invalid image magic; is this an MCUboot image?")