updated to use command instead of shell

tasks/main.yml

diff --git a/tasks/main.yml b/tasks/main.yml
index 2679c44..22b4c88 100644
--- a/tasks/main.yml
+++ b/tasks/main.yml
@@ -1,7 +1,7 @@
 ---
 # tasks file for apigee-opdk-setup-postgres-master
 - name: Postgres replication master
-  shell: '{{ apigee_service }} apigee-postgresql setup-replication-on-master -f {{ opdk_installation_config_file }}'
+  command: '{{ apigee_service }} apigee-postgresql setup-replication-on-master -f {{ opdk_installation_config_file }}'
 
 - name: Validate postgres replication master
-  shell: '{{ apigee_service }} apigee-postgresql postgres-check-master'
+  command: '{{ apigee_service }} apigee-postgresql postgres-check-master'