fix(lint): allow .txt files

closes #1161

pkg/lint/rules/template.go

@@ -149,7 +149,7 @@ func validateQuotes(templateContent string) error {
 
 func validateAllowedExtension(fileName string) error {
 	ext := filepath.Ext(fileName)
-	validExtensions := []string{".yaml", ".tpl"}
+	validExtensions := []string{".yaml", ".tpl", ".txt"}
 
 	for _, b := range validExtensions {
 		if b == ext {
@@ -157,7 +157,7 @@ func validateAllowedExtension(fileName string) error {
 		}
 	}
 
-	return fmt.Errorf("file extension '%s' not valid. Valid extensions are .yaml or .tpl", ext)
+	return fmt.Errorf("file extension '%s' not valid. Valid extensions are .yaml, .tpl, or .txt", ext)
 }
 
 // validateNoMissingValues checks that all the {{}} functions returns a non empty value (<no value> or "")

pkg/lint/rules/template_test.go

@@ -31,11 +31,11 @@ func TestValidateAllowedExtension(t *testing.T) {
 	var failTest = []string{"/foo", "/test.yml", "/test.toml", "test.yml"}
 	for _, test := range failTest {
 		err := validateAllowedExtension(test)
-		if err == nil || !strings.Contains(err.Error(), "Valid extensions are .yaml or .tpl") {
-			t.Errorf("validateAllowedExtension('%s') to return \"Valid extensions are .yaml or .tpl\", got no error", test)
+		if err == nil || !strings.Contains(err.Error(), "Valid extensions are .yaml, .tpl, or .txt") {
+			t.Errorf("validateAllowedExtension('%s') to return \"Valid extensions are .yaml, .tpl, or .txt\", got no error", test)
 		}
 	}
-	var successTest = []string{"/foo.yaml", "foo.yaml", "foo.tpl", "/foo/bar/baz.yaml"}
+	var successTest = []string{"/foo.yaml", "foo.yaml", "foo.tpl", "/foo/bar/baz.yaml", "NOTES.txt"}
 	for _, test := range successTest {
 		err := validateAllowedExtension(test)
 		if err != nil {