Yarn fails to install on Xenial

[ehmicky]

Yarn can be installed on Focal (example logs).
But it fails on Xenial (example logs).

Installing yarn at version 1.17.0
Installing Yarn!
> Downloading tarball...
[1/2]: https://yarnpkg.com/downloads/1.17.0/yarn-v1.17.0.tar.gz --> /tmp/yarn.tar.gz.Zby7CLEURu
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
100    79  100    79    0     0    313      0 --:--:-- --:--:-- --:--:--   314
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
curl: (60) server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none
More details here: http://curl.haxx.se/docs/sslcerts.html
curl performs SSL certificate verification by default, using a "bundle" of Certificate Authority (CA) public keys (CA certs). If the default bundle file isn't adequate, you can specify an alternate file using the --cacert option.
If this HTTPS server uses a certificate signed by a CA represented in the bundle, the certificate verification probably failed due to a problem with the certificate (it might be expired, or the name might not match the domain name in the URL).
If you'd like to turn off curl's verification of the certificate, use the -k (or --insecure) option.
[2/2]: https://yarnpkg.com/downloads/1.17.0/yarn-v1.17.0.tar.gz.asc --> /tmp/yarn.tar.gz.Zby7CLEURu.asc
100    83  100    83    0     0    738      0 --:--:-- --:--:-- --:--:--   738
  0     0    0     0    0     0      0      0 --:--:-- --:--:-- --:--:--     0
curl: (60) server certificate verification failed. CAfile: /etc/ssl/certs/ca-certificates.crt CRLfile: none
More details here: http://curl.haxx.se/docs/sslcerts.html
curl performs SSL certificate verification by default, using a "bundle" of Certificate Authority (CA) public keys (CA certs). If the default bundle file isn't adequate, you can specify an alternate file using the --cacert option.
If this HTTPS server uses a certificate signed by a CA represented in the bundle, the certificate verification probably failed due to a problem with the certificate (it might be expired, or the name might not match the domain name in the URL).
If you'd like to turn off curl's verification of the certificate, use the -k (or --insecure) option.
 > Failed to download https://yarnpkg.com/downloads/1.17.0/yarn-v1.17.0.tar.gz.

This started about one hour ago.

Potentially related issues:

• Yarn Debian key expiry date updated (EXPKEYSIG 23E7166788B63E1E) yarnpkg/yarn#7866
• Download link is not working yarnpkg/yarn#8699

[ehmicky]

Closing in favor of https://github.com/netlify/pod-workflow/issues/303