Remove the depth argument while git cloning

The depth argument is incompatible with cloning a specific commit. This
change removes the argument.

Change-Id: If8a855407ca383d046615ae2a4b8992d2e4b34fd

helm-chart-collator/playbooks/roles/install_git_repo_charts/tasks/dependencies.yaml

@@ -5,7 +5,6 @@
     repo: "{{ chart_dependency['url'] }}"
     version: "{{ chart_dependency['sha'] | default('HEAD') }}"
     refspec: "{{ chart_dependency['refspec'] | default('refs/heads/master') }}"
-    depth: 1
 
 - name: ensure the parent's charts directory exists
   file:

helm-chart-collator/playbooks/roles/install_git_repo_charts/tasks/main.yaml

@@ -5,7 +5,6 @@
     repo: "{{ chart['url'] }}"
     version: "{{ chart['sha'] | default('HEAD') }}"
     refspec: "{{ chart['refspec'] | default('refs/heads/master') }}"
-    depth: 1
 
 - include_tasks: dependencies.yaml
   loop: "{{ chart['dependencies'] | default([]) }}"