piuparts's command to establish the CODENAME is broken for experimental (rc-buggy)

This https://salsa.debian.org/salsa-ci-team/pipeline/-/blob/master/salsa-ci.yml#L626 is broken:

wget -O - https://deb.debian.org/debian/dists/experimental/Release | awk "/^Codename:/ { print \$2 }" | cut -d- -f1
--2023-06-08 14:07:26--  https://deb.debian.org/debian/dists/experimental/Release
Resolving deb.debian.org (deb.debian.org)... 151.101.218.132, 2a04:4e42:33::644
Connecting to deb.debian.org (deb.debian.org)|151.101.218.132|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 99292 (97K)
Saving to: ‘STDOUT’

-                                                           100%[========================================================================================================================================>]  96.96K  --.-KB/s    in 0.04s   

2023-06-08 14:07:26 (2.17 MB/s) - written to stdout [99292/99292]

rc

Example failing job: https://salsa.debian.org/santiago/pytango/-/jobs/4285535#L139