To write out an ISO 8601 timestamp in the current language, you can use the date_l10n shortcode:

Writing

{{% date_l10n "2020-10-20" %}}

will result in

2020-10-20

You can optionally specify a different formatting layout:

For example, the following

{{% date_l10n "2020-10-20" ":date_short" %}}

will result in

:date_short