Initialize Steps with a NewSTEPNAME function [#67]

This seems to be be a more natural separation of concerns--the knowledge
of which config fields map to which parts of a Step belong to the Step,
not to the Plan.

internal/run/help.go

@@ -2,6 +2,7 @@ package run
 
 import (
 	"fmt"
+	"github.com/pelotech/drone-helm3/internal/env"
 )
 
 // Help is a step in a helm Plan that calls `helm help`.
@@ -10,6 +11,13 @@ type Help struct {
 	cmd         cmd
 }
 
+// NewHelp creates a Help using fields from the given Config. No validation is performed at this time.
+func NewHelp(cfg env.Config) *Help {
+	return &Help{
+		HelmCommand: cfg.Command,
+	}
+}
+
 // Execute executes the `helm help` command.
 func (h *Help) Execute(cfg Config) error {
 	if err := h.cmd.Run(); err != nil {