bug#45358: bootstrap fails due to a certificate mismatch

[j-james]

When running ./bootstrap in a freshly-cloned repository, it seems to either 
not find some files it wants to or doesn't trust https://translationproject.org.

Connecting to https://translationproject.org in a (non-wget) web browser works 
fine.

The following is the output of ./bootstrap.
```
./bootstrap: Bootstrapping from checked-out coreutils sources...
./bootstrap: consider installing git-merge-changelog from gnulib
./bootstrap: getting gnulib files...
Submodule 'gnulib' (git://git.sv.gnu.org/gnulib.git) registered for path 
'gnulib'
Cloning into '/home/teal/Projects/coreutils/gnulib'...
Submodule path 'gnulib': checked out '8183682cc4436bee18007d61bc79938eaf78619a'
./bootstrap: getting translations into po/.reference for coreutils...
Loaded CA certificate '/etc/ssl/certs/ca-certificates.crt'
ERROR: The certificate of 'translationproject.org' is not trusted.
ERROR: The certificate of 'translationproject.org' doesn't have a known issuer.
```

Do let me know if you need more information, or if this is a duplicate report.

-- j-james