CI woes

[Per da Silva]

Dear MXNet community,

The credential rotaion and clean up had the undesirable side-effect of
triggering all of the PR jobs. This caused Jenkins to overflow and CI got
wonky.

After some computer hacking we've managed to get everything back to normal.
Unfortunately, this may have reset the state of the some of the PRs that
had already been through CI successfully. Please retrigger your PR, with
our apologies.

Cheers,

Per

Jenkins possibly compromised

[Marco de Abreu]

Hello dev@,

we noticed some fishy logs on our Jenkins and are afraid that a successful
attack might have happened. Thus, we are taking security precautions and
rotating all credentials and revoking active session.

As part of this process, we have to rotate the GitHub webhook secret. This
update requires communication with Apache Infra, which will render Jenkins
unusable for PR verification until the secret has been updated on Apache
Infras side.

Please excuse any inconveniences this may have caused.

Best regards,
Marco