alpine-amd64-node10-tf-a: add OpenJDK 11 package

Signed-off-by: Fathi Boudra <fathi.boudra@linaro.org>
Change-Id: I3850b1b5d62ec58a678ecaf0a085a7ec13edec20
diff --git a/alpine-amd64-node10-tf-a/Dockerfile b/alpine-amd64-node10-tf-a/Dockerfile
index b51f62a..a04963c 100644
--- a/alpine-amd64-node10-tf-a/Dockerfile
+++ b/alpine-amd64-node10-tf-a/Dockerfile
@@ -7,7 +7,7 @@
 
 RUN set -e ;\
     # install deps
-    apk add openssh bash sudo ;\
+    apk add bash openjdk11 openssh sudo ;\
     # Setup buildslave user for Jenkins
     adduser buildslave -D -s /bin/bash ;\
     echo "buildslave:$BUILDSLAVE_PASSWORD" | chpasswd ;\