ci-yadp-builder-sanity: fix typo calling yadp_builder.py

In a previous commit the ".py" suffix was left off of
the call to the yadp_builder.py script.  This change
restores it so the check can pass.

Signed-off-by: Kelley Spoon <kelley.spoon@linaro.org>
Change-Id: I0ee753c6415f04a0bb9896189ed2ebf967ce16ec
diff --git a/ci-yadp-builder-sanity.yaml b/ci-yadp-builder-sanity.yaml
index c184d48..d5c4dfc 100644
--- a/ci-yadp-builder-sanity.yaml
+++ b/ci-yadp-builder-sanity.yaml
@@ -58,7 +58,7 @@
             git fetch https://review.trustedfirmware.org/${GERRIT_PROJECT} ${GERRIT_REFSPEC}
             git checkout -q FETCH_HEAD
 
-            python3 yadp_builder --dryrun
+            python3 yadp_builder.py --dryrun
     publishers:
         - email:
             recipients: 'linaro-infrastructure-errors@lists.linaro.org'