Describe the bug

I can't set DD.MM.YYYY format, because function isValidFormat returns false.
I can't go with workaround like isDate("19.08.2021", { format: 'DD/MM/YYYY', delimiters: ["/", "."] }); because it approves dates with "/" delimeter

Examples
isDate("19/08/2021", { format: 'DD.MM.YYYY', delimiters: ["."], strictMode: true }); returns false

Additional context
Validator.js version: 13.6.1
Node.js version: 12.15.0
OS platform: [linux]