Use base64 strings for chart repo certs [#74]

This should be a more flexible option since certificates aren't likely
to be part of the actual workspace and may be environment-dependent. It
also mirrors the kube_certificate, which is nice.

internal/run/upgrade.go

@@ -22,7 +22,7 @@ type Upgrade struct {
 	force         bool
 	atomic        bool
 	cleanupOnFail bool
-	caFile        string
+	certs         *repoCerts
 
 	cmd cmd
 }
@@ -44,7 +44,7 @@ func NewUpgrade(cfg env.Config) *Upgrade {
 		force:         cfg.Force,
 		atomic:        cfg.AtomicUpgrade,
 		cleanupOnFail: cfg.CleanupOnFail,
-		caFile:        cfg.RepoCAFile,
+		certs:         newRepoCerts(cfg),
 	}
 }
 
@@ -98,9 +98,7 @@ func (u *Upgrade) Prepare() error {
 	for _, vFile := range u.valuesFiles {
 		args = append(args, "--values", vFile)
 	}
-	if u.caFile != "" {
-		args = append(args, "--ca-file", u.caFile)
-	}
+	args = append(args, u.certs.flags()...)
 
 	args = append(args, u.release, u.chart)
 	u.cmd = command(helmBin, args...)