[fix] Airflow Modified subpath configmap mount fails

Because of a kubernetes bug [0] when a container which
is mounted with the subpath option, the configmap is
changed and then the container restarts the mounting of
the configmap fails.

This PS uses the projected key for volume definitions
as a workaround.

[0] https://github.com/kubernetes/kubernetes/issues/68211

Change-Id: I6820a0f963c5b28e1674ea58214ffc86009db4dd

charts/shipyard/templates/statefulset-airflow-worker.yaml

@@ -183,13 +183,23 @@ spec:
               mountPath: {{ .Values.conf.airflow.core.base_log_folder }}
       volumes:
         - name: airflow-etc
-          configMap:
-            name: airflow-etc
+          projected:
             defaultMode: 0444
+            sources:
+              - configMap:
+                  name: airflow-etc
+                  items:
+                    - key: airflow.cfg
+                      path: airflow.cfg
         - name: shipyard-etc
-          configMap:
-            name: shipyard-etc
+          projected:
             defaultMode: 0444
+            sources:
+              - configMap:
+                  name: shipyard-etc
+                  items:
+                    - key: shipyard.conf
+                      path: shipyard.conf
         - name: airflow-bin
           configMap:
             name: airflow-bin