Exclude non-artifacts from the owners plugin output jars

The Bazel build target generates a lot of non-artifacts
that should be ignored when stamping the output files
for being archived into the Gerrit-CI outputs.

Change-Id: If73dea36f8b99be63e1b3beb1931c3c3fd20fde0
diff --git a/jenkins/gerrit-bazel-build-owners-plugin.sh b/jenkins/gerrit-bazel-build-owners-plugin.sh
index 737808c..a755189 100644
--- a/jenkins/gerrit-bazel-build-owners-plugin.sh
+++ b/jenkins/gerrit-bazel-build-owners-plugin.sh
@@ -28,7 +28,7 @@
     bazelisk test $target/... //tools/bzl:always_pass_test
 done
 
-for JAR in $(find bazel-bin/plugins/ -name {name}*.jar)
+for JAR in $(find bazel-bin/plugins/ -name {name}*.jar | egrep -e '(stamped|tests|header)' -v)
 do
     PLUGIN_VERSION=$(git describe  --always origin/{branch})
     echo -e "Implementation-Version: $PLUGIN_VERSION" > MANIFEST.MF