fix lint not failing in windows for bad template yamls

Signed-off-by: Karuppiah Natarajan <karuppiah7890@gmail.com>

pkg/lint/rules/template.go

@@ -100,7 +100,8 @@ func Templates(linter *support.Linter, values map[string]interface{}, namespace
 		// NOTE: disabled for now, Refs https://github.com/helm/helm/issues/1037
 		// linter.RunLinterRule(support.WarningSev, path, validateQuotes(string(preExecutedTemplate)))
 
-		renderedContent := renderedContentMap[filepath.Join(chart.Name(), fileName)]
+		templatePath := filepath.Join(chart.Name(), fileName)
+		renderedContent := renderedContentMap[filepath.ToSlash(templatePath)]
 		var yamlStruct K8sYamlStruct
 		// Even though K8sYamlStruct only defines Metadata namespace, an error in any other
 		// key will be raised as well