Update dependencies (#5518)

vendor/gopkg.in/src-d/go-git.v4/options.go

@@ -186,6 +186,9 @@ type PushOptions struct {
 	// Progress is where the human readable information sent by the server is
 	// stored, if nil nothing is stored.
 	Progress sideband.Progress
+	// Prune specify that remote refs that match given RefSpecs and that do
+	// not exist locally will be removed.
+	Prune bool
 }
 
 // Validate validates the fields and sets the default values.
@@ -242,6 +245,11 @@ type CheckoutOptions struct {
 	// Force, if true when switching branches, proceed even if the index or the
 	// working tree differs from HEAD. This is used to throw away local changes
 	Force bool
+	// Keep, if true when switching branches, local changes (the index or the
+	// working tree changes) will be kept so that they can be committed to the
+	// target branch. Force and Keep are mutually exclusive, should not be both
+	// set to true.
+	Keep bool
 }
 
 // Validate validates the fields and sets the default values.