Consider imagePullPolicy for init containers (#317)

The default behaviour for container image pulls depend on different values
such as image tag usage and its value.
See https://kubernetes.io/docs/concepts/containers/images/#imagepullpolicy-defaulting

It leads to an unintended behaviour for this Helm Chart. Kubernetes
will always pull the image for init containers when using the `latest`
Gitea image tag, even if `Values.image.pullPolicy` defines a different
value for the runtime container.

Reviewed-on: https://gitea.com/gitea/helm-chart/pulls/317
Reviewed-by: techknowlogick <techknowlogick@gitea.io>
Reviewed-by: Gusted <williamzijl7@hotmail.com>
Co-authored-by: justusbunsi <justusbunsi@noreply.gitea.io>
Co-committed-by: justusbunsi <justusbunsi@noreply.gitea.io>

templates/gitea/statefulset.yaml

@@ -48,6 +48,7 @@ spec:
       initContainers:
         - name: init-directories
           image: "{{ include "gitea.image" . }}"
+          imagePullPolicy: {{ .Values.image.pullPolicy }}
           command: ["/usr/sbin/init_directory_structure.sh"]
           env:
             - name: GITEA_APP_INI
@@ -78,6 +79,7 @@ spec:
             {{- toYaml .Values.containerSecurityContext | nindent 12 }}
         - name: init-app-ini
           image: "{{ include "gitea.image" . }}"
+          imagePullPolicy: {{ .Values.image.pullPolicy }}
           command: ["/usr/sbin/config_environment.sh"]
           env:
             - name: GITEA_APP_INI
@@ -118,6 +120,7 @@ spec:
         - name: configure-gitea
           image: "{{ include "gitea.image" . }}"
           command: ["/usr/sbin/configure_gitea.sh"]
+          imagePullPolicy: {{ .Values.image.pullPolicy }}
           securityContext:
             {{- /* By default this container runs as user 1000 unless otherwise stated */ -}}
             {{- $csc := deepCopy .Values.containerSecurityContext -}}