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/lint.go

@@ -2,6 +2,7 @@ package run
 
 import (
 	"fmt"
+	"github.com/pelotech/drone-helm3/internal/env"
 )
 
 // Lint is an execution step that calls `helm lint` when executed.
@@ -14,6 +15,17 @@ type Lint struct {
 	cmd          cmd
 }
 
+// NewLint creates a Lint using fields from the given Config. No validation is performed at this time.
+func NewLint(cfg env.Config) *Lint {
+	return &Lint{
+		Chart:        cfg.Chart,
+		Values:       cfg.Values,
+		StringValues: cfg.StringValues,
+		ValuesFiles:  cfg.ValuesFiles,
+		Strict:       cfg.LintStrictly,
+	}
+}
+
 // Execute executes the `helm lint` command.
 func (l *Lint) Execute(_ Config) error {
 	return l.cmd.Run()