Bug 27939: Update yarn.lock file

Bug 27939: Update yarn.lock file

There is a minor security vulnerability, it is good to fix it even if there is no impact on security: yarn is only used for dev purpose.

The the logs of https://wiki.koha-community.org/wiki/Development_IRC_meeting_24_February_2021

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
https://bugs.koha-community.org/show_bug.cgi?id=27938

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>