ansible: ttcn3: install netcat-openbsd

Make nc available on jenkins nodes running ttcn3 tests, as it is now
used by ttcn3-hss-test-ogs.

Related: docker-playground Iebeefd9689ae2efa54678b99ff929ca255ec64d1
Change-Id: I397d4fe33813b083b61cdabb1d00ab4ea63a456b

ansible/roles/osmocom-jenkins-slave/tasks/ttcn3-slave.yml

@@ -1,4 +1,11 @@
 ---
+- name: install programs used in jenkins.sh
+  apt:
+    name:
+      - netcat-openbsd
+    cache_valid_time: 3600
+    update_cache: yes
+    install_recommends: no
 
 - name: ensure jenkins folder exists
   become: yes