Amend gatling-git artifact name

Artifact name has been changed in another CS:
https://review.gerrithub.io/c/GerritForge/gatling-git/+/461284

CI scripts need to reflect this change.

Change-Id: I4113abbd15f1c7f9cb47318791ffdda152cf9819
diff --git a/jenkins/gatling-git-extension.yaml b/jenkins/gatling-git-extension.yaml
index 5fa7acc..90cd4f8 100644
--- a/jenkins/gatling-git-extension.yaml
+++ b/jenkins/gatling-git-extension.yaml
@@ -49,7 +49,7 @@
          done
     publishers:
       - archive:
-         artifacts: '**/target/**/gatling-git-assembly*.jar*'
+         artifacts: '**/target/**/gatling-git-extension.jar*'
 
 - project:
     name: gatling-git-sbt-{branch}