Call helm dependency update when so instructed [#25]

As with Lint, I have no idea whether the --namespace flag actually
matters here. I don't think it will hurt, though!

internal/helm/plan.go

@@ -96,7 +96,9 @@ func (p *Plan) Execute() error {
 
 var upgrade = func(cfg Config) []Step {
 	steps := initKube(cfg)
-
+	if cfg.UpdateDependencies {
+		steps = append(steps, depUpdate(cfg)...)
+	}
 	steps = append(steps, &run.Upgrade{
 		Chart:        cfg.Chart,
 		Release:      cfg.Release,
@@ -113,6 +115,9 @@ var upgrade = func(cfg Config) []Step {
 
 var uninstall = func(cfg Config) []Step {
 	steps := initKube(cfg)
+	if cfg.UpdateDependencies {
+		steps = append(steps, depUpdate(cfg)...)
+	}
 	steps = append(steps, &run.Uninstall{
 		Release: cfg.Release,
 		DryRun:  cfg.DryRun,
@@ -122,11 +127,15 @@ var uninstall = func(cfg Config) []Step {
 }
 
 var lint = func(cfg Config) []Step {
-	lint := &run.Lint{
-		Chart: cfg.Chart,
+	steps := make([]Step, 0)
+	if cfg.UpdateDependencies {
+		steps = append(steps, depUpdate(cfg)...)
 	}
+	steps = append(steps, &run.Lint{
+		Chart: cfg.Chart,
+	})
 
-	return []Step{lint}
+	return steps
 }
 
 var help = func(cfg Config) []Step {
@@ -147,3 +156,11 @@ func initKube(cfg Config) []Step {
 		},
 	}
 }
+
+func depUpdate(cfg Config) []Step {
+	return []Step{
+		&run.DepUpdate{
+			Chart: cfg.Chart,
+		},
+	}
+}