Add jenkins plugin EnvInject

Change-Id: I618e17037bc8580ec0b400c67a92396e3cb91a96
diff --git a/Dockerfile b/Dockerfile
index b3dadfc..dc2ba76 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -85,6 +85,7 @@
         discard-old-build \
         docker-workflow \
         email-ext \
+        envinject \
         extended-choice-parameter \
         extensible-choice-parameter \
         gerrit-trigger \