Fix: yml is valid type (#206)

* Fix: yml is valid type

* Make file extension matching case-insensitive

* make exclude-file-types string lowercase before using it

---------

Co-authored-by: Clayton Kehoe <118750525+kehoecj@users.noreply.github.com>

cmd/validator/validator.go

@@ -83,7 +83,9 @@ func validatorUsage() {
 func getFileTypes() []string {
 	options := make([]string, 0, len(filetype.FileTypes))
 	for _, typ := range filetype.FileTypes {
-		options = append(options, typ.Name)
+		for extName := range typ.Extensions {
+			options = append(options, extName)
+		}
 	}
 	sort.Strings(options)
 	return options
@@ -154,6 +156,7 @@ Supported formats: standard, json, junit (default: "standard")`,
 	}
 
 	if *excludeFileTypesPtr != "" {
+		*excludeFileTypesPtr = strings.ToLower(*excludeFileTypesPtr)
 		if !validateFileTypeList(strings.Split(*excludeFileTypesPtr, ",")) {
 			return validatorConfig{}, errors.New("Invalid exclude file type")
 		}