test(ci-broker.md): add 0.17.0 release to upgrade list — radicle-ci-broker

Drop older releases, the 0.17.0 release upgrade test verify those.

Signed-off-by: Lars Wirzenius liw@liw.fi

 given a directory reports
 when I touch file run-list.txt
 when I run ./env.sh bash -x verify-upgrade run-list.txt 64e76a97a817c87a72bb4cded661488c225410b7
 when I run ./env.sh bash -x verify-upgrade run-list.txt 768af45e7ee9e0606a89e4819ba312cfef558142
 when I run ./env.sh bash -x verify-upgrade run-list.txt 46963aaa4f6d1a7a7c0f329ab36ca2a510993213
 when I run ./env.sh bash -x verify-upgrade run-list.txt HEAD
 ~~~