Revert "config: find yaml config if input no extension"

This reverts commit e098c0b.

Author: oleg-jukovec

cli/util/util.go

@@ -802,10 +802,6 @@ func GetYamlFileName(fileName string, mustExist bool) (string, error) {
 		fileBaseName = strings.TrimSuffix(fileName, ".yaml")
 	case ".yml":
 		fileBaseName = strings.TrimSuffix(fileName, ".yml")
-	case ".":
-		fileBaseName = strings.TrimSuffix(fileName, ".")
-	case "":
-		fileBaseName = fileName
 	default:
 		return "", fmt.Errorf("provided file '%s' has no .yaml/.yml extension", fileName)
 	}